Intel Skylake Speed Shift Technology - Power Performance and Energy Efficiency

In 2015, for the first time in history, Intel had two major launches and one of those is going to be covered today by us. In 2013, Intel had launched their Haswell microarchitecture on the 22nm process node which had served the market up till late 2014. Everyone had anticipated Intel's 14nm node to arrive in the market by 2H 2014 but production issues meant that we won't see mass production of 14nm chips commence until late 2014. Due to production issues, Intel had to shift the majority of their 14nm chips to 2015 and consumers were stuck with the Haswell chips for a good two years. Intel did launch a specific SKU family, codenamed Core M (Broadwell-Y) in 2014 but the majority of the lineup was pushed to 2015. With the Tick-Tock cycle disrupted, Intel had to re-focus and made changes to their Tick-Tock roadmap and developed a 2.5 year cadence which revolves around a single Tick and two Tocks in the coming years.

Intel's Tock Tock Strategy
Architecture	Process	Tick/Tock	Release
Conroe	65nm	Tock	2006
Penryn	45nm	Tick	2007
Nehalem	45nm	Tock	2008
Westmere	32nm	Tick	2010
Sandy Bridge	32nm	Tock	2011
Ivy Bridge	22nm	Tick	2012
Haswell	22nm	Tock	2013
Broadwell	14nm	Tick	2014
Skylake	14nm	Tock	2015

Come 2015 and we see an abundance of Broadwell chips launching at CES 2015 with more chips to follow in mid of 2015. Intel released their Broadwell-K desktop parts in June 2015 with two chips, the Core i7-5775C and Core i5-5675C. Both processors were based on the Broadwell architecture with a 5.5% IPC improvement and built on the 14nm process node. The Broadwell desktop processors were faster than the Devil's Canyon chips (Haswell Refresh) while featuring lower clock speeds, had an unlocked multiplier to allow overclocking and also featured Iris Pro graphics with embedded DRAM (128 MB L4 cache). The Iris Pro graphics chip was a nice but costly addition to the processors and resulted in a slight increase to the price of the processors compared to the previous generation parts. And while the processors retained compatibility with the existing Z97 series of motherboards with LGA 1150 socket, it made little sense to upgrade to these chips if users were already using a good Haswell processor.

In 2015, Intel had another major launch planned for 5th August. This was related to their Skylake architecture which was going to debut on Gamescom 2015. While Intel previously focused on mobility launches first, this was the first time in several years where Intel had emphasized more on the desktop parts with a fully unlocked family of Skylake processors planned for launch along with their Z170 series platform. The Core i7-6700K and Core i5-6600K are the top most chips in the Skylake-K family. Users had been eyeing on Skylake since a while now to see whether Intel pushes performance dramatically over the previous generation so that they can push for upgrades from their older processors. The wait is over and Intel had finally taken off the wraps from the Skylake architecture and processor family. Today, we test the Core i7-6700K processor to find out whether it is a worthy upgrade over Haswell and more importantly, over Sandy Bridge where most of the PC user base will be upgrading from.

Featuring improved performance, better power efficiency and faster graphics cores, the Skylake processors are the first mainstream family from any chip maker to be fully compatible with DDR4 memory while future processors are on the road and will integrate faster eDRAM based cache that will significantly boost/enhance performance while reducing latency so that applications work and load faster. Several key technologies are part of the Intel Skylake family that include faster memory, storage solutions, more PCI-E lanes, support for future NvME based SSDs and even Octane (3D XPoint) SSDs. The article we are compiling today will give you a brief insight on what Skylake is and what architectural changes were incorporated to make Skylake faster and more efficient than its predecessor.

Intel’s latest System-on-Chip (SoC) microarchitecture, code name Skylake. It is built on Intel’s leading 14nm process technology. This “tock” microarchitecture was completely redesigned to bring new IPs and integrations, great performance and reduced power consumption. via Intel

Before we move in to the performance reviews, we need to know what is Skylake all about and what kind of  architecture focused enhancements are built inside it. The analysis will revolve around the CPU architecture details followed by the GPU architectur, the several Hardware P-states and finally an insight into the new platform features that will be featured on Skylake desktop and mobility processors.

We have all been waiting to know the details for Intel's 6th generation Skylake processors and the time has finally come when we can fully unwrap the details of Intel's latest 14nm core architecture. To start off, we would like to tell you four specific features that Skylake is going to focus on that include Scalability, power, performance, media and graphics. The Intel Skylake development started off with just a 3x TDP scale, 2x form factor range and a classic set of PC IO features but ended with 20x TDP scale, 4x form factor range and delivering a wide range of I/O features across PC and tablet devices that are going to launch in Q4 2015.

Technically, each Skylake core is bigger and wider, features better instructions per clock and improved power efficiency. The basic core block of a Skylake chip includes four of these cores which share a LLC through an enhanced interconnect ring known as the SOC Ring. The die includes graphics processors that range from GT1, GT2, GT3 to more performance oriented and advanced designs that include GT3e and GT4e with embedded DRAM (L4 Cache up to 128 MB) that feature support for OpenCL 2.0, DirectX 12 and OpenGL 4.4. The system agent includes the dual channel DDR4 memory controller, the display system for embedded and external displays while the PCI-Express lanes can be used to connect discrete graphics card for higher PC performance on desktop setups. Audio DSPs and sensor hubs also get an update with Skylake while a single integrated camera ISP can also be found inside the Skylake die for better imaging quality and lastly, Skylake delivers extended overclocking capabilities which we will talk about in a short moment.

So these are the general details of the Skylake microarchitecture but the core needs to be examined a bit more. Skylake features a vastly improved front end design with improved branch predictions that comes with a higher capacity compared to Haswell and has wider instruction supply with deeper buffers and fast prefetch. The deeper out-of-order buffers extract more instructions parallelism while the improved EUs (Execution Units) have lower latency, more units, can power down when idle and improve AES-GCM by 17% and AES-CBC by 33%. The load and store bandwidth is also larger with prefetcher improvements, deeper store buffer, better L2 cache miss bandwidth, improved page miss handling and new instructions for better cache management. Hyper threading performance is also improved with more wider retirement and Skylake gets higher queues of 64 per thread compared to 56/thread on Haswell and 28/thread on Sandy Bridge. The more parallelism optimized architecture of Skylake enhances the FP register file to 180 versus 168 on Haswell, scheduled entries to 97 versus 60 on Haswell to extract more parallelism out of the core design. The window size has now been increased exceptionally to 224 compared to 168 on Sandy Bridge and 192 on Haswell.

The new interconnect ring delivers double the throughput (bandwidth) without sacrificing power. LLC (Last Level Cache) throughput is also doubled with cache miss handling, the DDR4 DRAM as a whole deliver vastly improved bandwidth to the system while eDRAM based chips can effectively reduce latency and transfer speeds within the die block. The system acts as a fully coherent design to share and manage memory and data transfer and store loads in the processor. We won't dive into the power details in this topic since it is covered in the next page but let's dive into the overclocking architecture infused in Skylake.

Intel Skylake Recieves Full Range BCLK Improvements and Finer Grain Tuning For DDR4 Memory

With Skylake, Intel is leveraging their overclock support on their processors. Intel already added significant overclocking features on Haswell with real-time overclocking software, ration base clock overclocking and latest Intel XMP modes with their Intel Extreme Tuining utility. With Skylake, Intel adds full range BCLK tune options and improved DDR4 memory overclocking. With a fully unlocked turbo design that is controllable through software and BIOS, the full BCLK overclocking allows full range, 1 MHz increments over Haswell's Ration-based tune in 100/125/166 MHz. The unlocked core ratios can be tuned up to 83 in 100 MHz increments with complete turbo overrides for voltage, power limits, IccMax. The Skylake processors also fully support DDR4 overclocking with override capabilities of up to 4133 MT/s and DDR steps tuning in 100/133 MHz compared to 200/266 MHz with finer grain increments. Even the graphics clock can be tuned with ratios up to 60 in 50 MHz increments, with fully turbo voltage controls.

Intel has also focused on Top-down Microarchitecture Analysis Method (TMAM) is an industry-proven systematic approach that identifies performance bottlenecks in out-of-order cores. Identifying true bottlenecks lets developers focus software tuning to remediate them and improve efficiently on same hardware. TMAM simplifies cycle-accounting using microarchitecture independent metrics organized in one single hierarchy which makes analysis simple. Using TMAM, the high-learning curve associated with each microarchitecture generation is replaced by a structured drill-down that guides the user to true performance limiters.

Note: Before ending this section, I need to point out that Intel clarified that there's no Inverse Hyper Threading found on Skylake CPUs and everything that has been in the talks for the past few days are rumors.

Moving on, we have the graphics architectural analysis from Intel that is based around their Gen9 GPU. The details will involve all the key information and insights on Intel's Skylake's CPU and GPU architecture. Right now, we can show you the full details regarding the Skylake Gen9 GPU graphics architecture which will be divided into three *initial* tiers that include GT2, GT3/e and GT4/e.

The details Intel provides on their Skylake iGPUs include a block diagram for their Core i7-6700K processor which launched earlier this month as the flagship offering on the Z170 platform. The chip which Intel term as a SOC (System on Chip) houses four CPU cores with a shared LLC cache that's interconnected through a SOC Ring which is a bi-directional, 32-byte wide bus and further connects with the iGPU and System agent. All the memory transactions to/from CPU cores and to/from Intel iGPUs are also handled by this SOC Ring, through the system agent and the unified DRAM controller. Now Intel would like to call it a SOC but its in fact a Semi-SOC since the PCH (Southbridge) is still housed on the motherboard while the Northbridge has been moved to the CPU for quite some time now. Intel has saved a lot of die space with their 14nm CPUs but moving the PCH to the chip itself will require a lot of room, even more if you are going to feature the eDRAM on the side of the chip package. A suitable example would be the case Broadwell Core i7-5775C that houses a 128 MB of eDRAM cache on the core package alongside the main die. That along with the several transistors make up for a lot of room and leaves little space for any further addition to the unit.

Some of the key improvements and changes for the Skylake Gen9 graphics include:

Intel Skylake Gen9 Graphics Features:

Gen9 Memory Hierarchy Refinements:

• Coherent SVM write performance is significantly improved via new LLC cache management policies.
• The available L3 cache capacity has been increased to 768 Kbytes per slice (512 Kbytes for application data).
• The sizes of both L3 and LLC request queues have been increased. This improves latency hiding to achieve better effective bandwidth against the architecture peak theoretical.
• In Gen9 EDRAM now acts as a memory-side cache between LLC and DRAM. Also, the EDRAM memory controller has moved into the system agent, adjacent to the display controller, to support power efficient and low latency display refresh.
• Texture samplers now natively support an NV12 YUV format for improved surface sharing between compute APIs and media fixed function units.

Gen9 Compute Capability Refinements:

• Preemption of compute applications is now supported at a thread level, meaning that compute threads can be preempted (and later resumed) midway through their execution.
• Round robin scheduling of threads within an execution unit.
• Gen9 adds new native support for the 32-bit float atomics operations of min, max, and compare/exchange. Also the performance of all 32-bit atomics is improved for kernel scenarios that issued multiple atomics back to back.
• 16-bit floating point capability is improved with native support for denormals and gradual underflow.

Gen9 Product Configuration Flexibility:

• Gen9 has been designed to enable products with 1, 2 or 3 slices.
• Gen9 adds new power gating and clock domains for more efficient dynamic power management. This can particularly improve low power media playback modes.

Intel Skylake GT2/e Graphics With 24 EUs and Optional eDRAM

The first Gen9 graphics that we are going to talk about is the GT2 graphics core that is found on the Graphics 530 chip featured on both Skylake desktop (unlocked) processors. As was the case with the Haswell processors, each slice of the new graphics block can either be combined or reduced to form different graphics SKUs for various range of products. Each slice is comprised of various subslice that include the foundation of the Gen9 graphics block, the EU (Execution Unit). Each EU is an SMT / IMT combination (Simultaneous and Fine-Grained Interleaved Multi-Threading) with multiple SIMD ALUs featured across multiple threads. Skylake gets 128 general purpose registers per EU with 32 bytes of register stores and 4 Kbytes of general purpose register files. Since Gen9 has 7 threads per EU, these amount to 28 Kbytes of GRF's on each EU. The computation is handled by a pair of SIMD FPUs that can execute up to four 32-bit floating-point or integer and 16-bit floating point or integer operations while retaining the FP64 double precision compute capabilities. The integration of 16-bit floating point is new in Skylake processors with twice the operational speeds of FP32 and a similar path to what NVIDIA is planning to incorporate on their Pascal graphics processors next year.

The GT2 graphics chip has three subslices with 8 EUs per subslice. This makes a 24 EUs slice which is connected to the L3 cache through the SOC ring we talked about earlier. Each subslice comes with a local thread dispatcher which connects the different subslices as a single unified slice. They also come with the sampler (read-only memory fetch) unit that is used for the sampling of tiled (not tiled) texture and image surfaces. It comes with its own Sampler L1 and L2 cache. The data port is a memory load/store unit while the latest GTI (Graphics Technology Interface) works as a gateway between the Gen9 iGPU and the rest of the chip.

The HD Graphics 530 chip housed inside the Core i7-6700K has a clock speed of 350 MHz base and 1150 MHz boost. With 24 Execution units and an improved design, we have seen an increase in overall graphics performance. More surprisingly, the 6700K die also houses an optional eDRAM controller that can feature 64 MB to 128 MB of eDRAM (L4) cache with frequencies of up to 1.6 GHz to increase bandwidth, reduce latency and improve performance on faster iGPUs. It is quite unnecessary to incorporate such high band width memory on the 6700K class processor but the optional controller does make it seem that we may find some GT2 chips with embedded DRAM.

Intel Skylake GT3/e Graphics With 48 EUs and eDRAM

The Skylake GT3 graphics also come in two variants, one with eDRAM and one without it. The chip houses 48 Execution units that are partitioned in two slices, each slice consisting of three subslices with 8 EUs per subslice. Each slice has its own L3 data cache and a unified memory interface. The chip will house up to 64 MB of L4 cache with the GT3e variants that come later this year.

Intel Skylake GT4/e Graphics With 72 EUs and eDRAM

Finally, we have the fastest graphics chip that Intel has ever made, the GT4 class integrated graphics chip. This Gen9 core combines three slices of 24 EUs where each slice is composed of three subslices of 8 EUs per subslice.  With three L3 data caches that are combined through the unified local memory interface in a large package, the chip will house up to 128 MB of L4 cache (eDRAM). The chip will featured on Iris Pro class processors with increased graphics performance compared to traditional iGPU based processors. At 1 GHz clock, the GT4e graphics chip can pump out 1152 GFlops of compute performance which is without taking in account the performance of the processing cores.

While we have seen the performance of Core i7-6700K and Core i5-6600K iGPUs which come close to the really low end discrete graphics cards available such as the Radeon R5 230 or the GeForce GT 720/730, both NVIDIA and AMD haven't actually released any discrete level parts in the market as of yet with their latest Radeon 300 series and GeForce 900 series lineup. Now AMD has a reason for not releasing discrete cards as the APUs they ship already come with GCN powered chips but discrete graphics cards market share in major markets such as China has drastically fallen down for these two GPU makers and more people are buying or aiming at the high-end graphics cards. This leaves a question whether the low-end discrete graphics market is going to end in a couple of years?

Well, neither did AMD or NVIDIA focused in performance improvement on the low-end sector, their low-end cards below the Radeon R7 360/260 or the GTX 950/750 is quite poor in terms of performance and retails at around $50 US which if user goes with an integrated graphics solution is a better option since that $50 US is saved for additional upgrades. The market here was wide open for AMD and Intel to leverage their own iGPU chips and they have done so but Intel seems to be doing it better. The chips Intel currently offer are only found on expensive processors but with a few passing generations, we can see the same or better performance scale down to mid-tier chips that are equivalent of an AMD APU retailing at around $150 US - $200 US. This will give user a decent processor that houses performance on par with a GeForce GTX 750 Ti class graphics card that can be a ideal budget PC built with low power consumption.

The concept of onboard graphics chips has been here for a long time, there was a time when all three giants used to integrate these chips on the main boards but with the shrinking desktop market, they had to revise their GPUs and focus their path. NVIDIA went the discrete and mobility route, ATi merged with AMD and offered discrete solutions, mobility solutions and APUs while Intel went an all out integrated route. Now when we look at the discrete market share of cards, we see NVIDIA dominating the graphics market with around 70-75% and AMD with a discrete market share of 25-30% up till Q4 '14 (based on figures compiled by Beyond3D) however when we take a look at the GPU market share which includes discrete, integrated, mobility chips, we see a bigger divide. The figures from John Peddie Research up till Q4 '14 show AMD at 13.61% market share, NVIDIA at 15% and Intel dominating the market with an insane 71.39% market share which is insanely high.

Now we know these numbers are not representative of the existing market as we have seen AMD and NVIDIA launching insanely high-performance graphics cards in the market and Intel introducing two new architectures with new graphics capabilities. But even if AMD and Intel do get a lead in graphics share, it won't nearly even touch Intel's dominance in the market and do note, Intel is known for their processors and their chipsets, not their graphics chips. So what led to this gain? Integration across the board, Intel has secured lots of AIB in the mobility world and that is where the market growth is at. In just a small fraction of time, Intel is on par with AMD's Carrizo APU that houses their latest Excavator and GCN 1.1 graphics core. Intel has a recipie of disaster cooked for AMD and NVIDIA in the entry to mid-range mobility market and possibly even in the discrete GPU market when we look into the next 3-5 years. But don't get surprised, Intel has certain limits to what they can do on existing silicon, unlike discrete GPUs, integrated solutions require cooling, higher power and the demand keeps on increasing. Intel won't certainly be able to tackle AMD or NVIDIA in the mid to high end discrete GPU market unless the come up with their own solution unlike the failed Larrabee which now serves the foundation of their Xeon Phi (MIC HPC Accelators) line.

Chip Name	GPU Core	GFlops (GPU Only)	GFlops (Whole Package)
AMD Radeon R7 360	Tobago Pro	1536 GFlops	N/A
NVIDIA GeForce GTX 750 Ti	Maxwell GM107	1389 GFlops	N/A
AMD Radeon R7 250X	Cape Verde XT	1216 GFlops	N/A
Intel Skylake Gen9 GT4/e	Intel Iris Pro 580	1152 GFlops @ 1 GHz	TBC
NVIDIA GeForce GTX 750	Maxwell GM107	1044 GFlops	N/A
AMD Radeon R9 M370X	Venus XT	992 GFlops	N/A
Intel Skylake Gen9 GT3/e	Intel Iris 560/570?	884 GFlops (Estimation)	TBC
AMD Carrizo FX-8800P	GCN 1.2	819 GFlops	1070 GFlops
Intel Core i7-5775C	Intel Iris Pro 6200	768 GFlops @ 1 GHz	883 GFlops
AMD Kaveri A10-7850K	GCN 1.1	737 GFlops	856 GFlops
Intel Core i7-5557U	Intel Iris 6100	724 GFlops	845 GFlops
AMD Richland A10-6800K	VLIW4	648 GFlops	779 GFlops
Intel Skylake Core i7-6700K	Intel HD 530	442 GFlops	TBC
Intel Haswell Core i7-4790K	Intel HD 4600	400 GFlops	512 GFlops

All this talk goes off to show that the integrated graphics cores from AMD and Intel might actually change the discrete market as we know it by reducing the need for entry level discrete class graphics. Now there are plans by AMD in the future to scale down several TFlops GPUs in APUs which are termed as HPC APUs. Specifically designed for server spaces, these high-end "TFlops class" SOCs from Intel, AMD and even NVIDIA if they get to enhance their GPGPU performance for Denver CPUs to rival the likes of high-end discrete cards. Now call me skeptical but I don't expect to see these parts several years ahead but once they do, things are going to become a lot more interesting in the graphics world.

Up till Skylake, Intel has made dramatic changes to the power management systems found on their new chips. With Skylake, Intel takes a step forward by reducing power consumption and enhancing efficiency by taking away a few things and integrating a few new things. We know that a Skylake SOC can consist of 2-4 CPU cores, graphics cores, media IPs, a ring interconnect, cache and ISA (Integrated System Agent). An SOC design can further more consist of an on-package PCH and eDRAM. Intel simply adds in a new unit known as PCU (Package Control Unit) that is a power management logic and controller firmware that can track internal statistics of the SOC, collects internal and external power telemetry (iMon, Psys) and can even interface to higher power management hierarchies such as OS, BIOS, EC, graphics driver and DPTF.

Intel also incorporates several hardware level P-states which divides the energy and frequency demands into several tiers and controlled by the operating system. This demand base algorithm of P-State is a bit slower as it leads into several P-states from energy efficient mode (min V) Pn, to P1 and P2 states and then P0 -1 core or P0-2 cores that deliver the highest frequency when demanded. With Skylake, Intel has housed their latest speed shift technology (hardware P-state) that is a highly dynamic power management system that can configure multi-core designs, AVX and accelerators to enhance efficiency. The power gating system is a lot more brute on Skylake that can even shut down AVX2 completely when its not in use.

By exposing the entire frequency range, Skylake will deliver smarter power management by allowing small form factors with larger turbo frequency range and finer grain, micro architectural observability by allowing both the hardware and software to share power and performance control. The lowest frequency with the latest management is now set to 100 MHz on Skylake.

Intel Skylake Hardware P-States:

• Operating system directed minimum quality of service, directive of desired performance and energy performance balancing
• Autonomous algorithms that self-manage the P-states within the OS directed range (normally full min to max range)
• Detecting user interaction and accelerating responsiveness
• Energy efficient race to halt
• Core duty cycling
• The power and power delivery controls including: PL1/2/3/TDC/Psys

The first round of processors launched in the Skylake family are focused towards the gaming and enthusiast crowd. These include the Core i7-6700K and Core i5-6600K processors. Intel has also launched several main stream chips in the lineup but our focus in today's review is the Core i7-6700K which is the flagship processor for the Skylake family.

ASUS sent us their latest Z170 Pro Gaming motherboard to test the Core i7-6700K processor. The motherboard features the latest LGA 1151 socket that supports Intel's 6th generation Skylake processors and comes with the Z170 chipset that offers new features and enhancements over previous generation motherboards. The product comes with a range of new utilities and design updates that allow better stability, overclocking support which has been detailed below.

Intel LGA 1151 Socket

The Intel LGA 1151 is the latest socket that features support for 6th generation Skylake processors. As denoted by its name, the LGA 1151 has a total of 1151 contact pins compared to 1150 on the LGA 1150 socket indicating that the new socket cannot support older generation processors.

The LGA 1151 socket is featured on the 100-Series chipset motherboards and will extend support to new CPUs which include Kaby Lake, which is the codename for Intel’s next generation 14nm processor that is planned for launch in 2016 for desktop PCs. Currently there are only two processors available on the 1151 socket, the Core i7-6700K and Core i5-6600K but a total of 18 mainstream Skylake-S processors are headed their way for launch in October 2015.

Price	$169.99
CPU	Intel Socket 1151 for 6th Generation Core i7/Core i5/Core i3/Pentium/Celeron Processors Supports Intel® 14 nm CPU Supports IntelTurbo Boost Technology 2.0
Chipset	Intel Z170
Memory	4 x DIMM, Max. 64GB, DDR4 3400(O.C.)/3333(O.C.)/3200(O.C.)/3100(O.C.)/3000(O.C.)/2933(O.C.)/2800(O.C.)/2666(O.C.)/2600(O.C.)/2400(O.C.)/2133 MHz Non-ECC, Un-buffered Memory Dual Channel Memory Architecture
Multi-GPU Support	Supports NVIDIA Quad-GPU SLI Technology Supports NVIDIA® 2-Way SLI Technology Supports AMD Quad-GPU CrossFireX Technology Supports AMD 3-Way CrossFireX Technology
Expansion Slots	2 x PCIe 3.0/2.0 x16 (Single at x16, dual at x8/x8, ) 1 x PCIe 3.0/2.0 x16 (max at x4 mode, ) 3 x PCIe 3.0/2.0 x1
Storage	1 x SATA Express port, Compatible with 2 x SATA 6.0 Gb/s ports 1 x M.2 Socket 3, with M Key design, type 2242/2260/2280/22110 storage devices support (Supports both SATA & PCIE SSD)*1 4 x SATA 6Gb/s port(s)
LAN	Intel I219V, 1 x Gigabit LAN Controller(s), GameFirst technology
Audio	SupremeFX 8-Channel High Definition Audio CODEC - Supports : Jack-detection, Multi-streaming, Front Panel MIC Jack-retasking - High quality 115 dB SNR stereo playback output
USB Ports	ASMedia® USB 3.1 controller : 1 x USB 3.1 port(s) (Type-A) ASMedia® USB 3.1 controller : 1 x USB 3.1 port(s) (Type-C, Reversible) Intel® Z170 chipset : 6 x USB 3.0/2.0 port(s) (4 at back panel, blue, 2 at mid-board) Intel® Z170 chipset : 8 x USB 2.0/1.1 port(s) (2 at back panel, black, 6 at mid-board)
Back I/O Ports	1 x PS/2 keyboard/mouse combo port(s) 1 x DVI 1 x D-Sub 1 x DisplayPort 1 x HDMI 1 x LAN (RJ45) port(s) 1 x USB 3.1 (red)Type-A 1 x USB 3.1 Type-C 4 x USB 3.0 2 x USB 2.0 1 x Optical S/PDIF out 5 x Audio jack(s)
Accessories	User's manual I/O Shield 4 x SATA 6Gb/s cable(s) 1 x M.2 Screw Package 1 x CPU installation tool 1 x Supporting DVD 1 x SLI bridge(s) 1 x 12 in 1 Cable Label (s)
Form Factor	Drivers ASUS Utilities ASUS EZ Update Anti-virus software (OEM version)

Intel did one thing right with the new socket and that’s the socket positioning which allows older coolers and mounting brackets to remain compatible with the newer socket. So if you have a old LGA 1150 socket cooler that you wish to use with the new LGA 1151 socket, It could be done so, but do note that while the socket looks the same as LGA 1150 socket, the processors are incompatible due to different pin layout so you don’t want to try putting an Haswell processor into the LGA 1151 socket otherwise it would damage the pins permanently.

Cooler Compatibility With LGA 1151 Socket

While Haswell processors ship with their own boxed coolers and cooler makers providing retention brackets for LGA 1150 compatibility, it should be noted that Intel has stopped offering boxed coolers with Skylake processor generation and users have to look forward to retail coolers. Intel does offer a separate boxed cooler but it will be a much better choice to get an AIB cooling solution since those offer better cooling performance. Older CPU coolers will remain compatible with the new socket and some manufacturers are provided updated retention brackets for the 1151 socket boards.

Intel 100-Series Z170 Platform Control Hub

Intel’s Skylake processors are compatible with the 100-Series “Lynx Point” chipset fused on the LGA 1150 socketed motherboards. There are different tiers of the chips on the Skylake platform which include Z170, H170 and B150. The Z170 chipset has been officially launched since over a month now while the H170 and B150 are marking their rounds in the market. The motherboard we would be testing today is based on the Z170 PCH. The following chart mentions key differences between both platform control hubs:

Item	9-Series “Lynx Point”	100-Series “Sunrise Point”
I/O Port flexibility	Yes	Yes
Total USB 3.0/2.0 Ports	14 USB Ports	24 USB Ports
USB 3.0 Capable Ports	Upto 6	Upto 10
xHCI Ports	All USB Ports by xCHI	All USB Ports by xCHI
PCI Express	Upto 8 PCI-e 3.0 (8GT/s) PCIe M.2 Storage Support	Upto 20 PCI-e 3.0 (8GT/s) PCIe M.2 Storage Support
Total SATA Ports	6 SATA	6 SATA (e-SATA)
SATA 6 GB/s Capable Ports	Upto 6	Upto 6
Legacy PCI	Legacy PCI on certain SKUs	Legacy PCI on certain SKUs
Digital Display I/F	Display moved to processor	Display moved to processor
Analog Display I/F	VGA/HDMI/DVI	VGA/HDMI/DVI
SPI	SFDP, Quad Read	SFDP, Quad Read

The Z170 Pro Gaming, as the name suggests, is a gaming motherboard that’s part of the legacy lineup. The motherboard comes in the standard packaging that includes a code for World of Warships inside the package. The motherboard has all sorts of labels on the front and back to highlight some of the features.

Inside the packaging are a few accessories that include a User's Manual, I/O Shield, 4 x SATA 6Gb/s cable(s), 1 x M.2 Screw Package, 1 x CPU installation tool, 1 x Supporting DVD, 1 x SLI bridge(s), 1 x 12 in 1 Cable Label (s).

Out of the box, we can see that the ASUS Z170 PRO Gaming is one of the several Gaming motherboards that adopts a black and red color scheme. The motherboard comes with a full black PCB which is a good thing and has the normal ATX form factor which can be equipped with ease in almost any mid to full tower chassis.

The motherboard comes with ASUS's DIGI+ design with DIGI+ VRM featuring high-quality components that include superior chokes and black durable capacitors featured across a 10 Phase PWM.

There's a single 8-Pin connector that is used to power the CPU socket. The board is a gaming oriented board that focuses on offering more I/O tools rather than overclocking features but there's still a good overclocking design implanted on the board to push Skylake CPUs beyond their reference specifications (clock speeds).

 

 

The motherboard comes with the latest DDR4 memory standard for Intel's mainstream platform. After Haswell-E, Skylake is the second platform from Intel to support the DDR4 memory standard and the Z170 Pro Gaming features support for Dual-Channel DDR4 DIMMs with speeds of up to 3400 MHz. The total capacity support by the motherboard is 64 GB.

There are two heatsinks featured on the PWM to keep the area cool when under loads. These heatsinks have an aluminum surface which helps dissipate heat into the heatsink block that are kept cool by cross-ventilation of airflow from the chassis fans.

The board comes with three PCI-e 3.0 x16 slots (x16/x8;x8/x4 electrical) and three PCI-e 3.0 x1 slots. Since the CPU packs 20 PCI-E lanes, its possible for graphics card to operate with full 8.0 GT/s speed of the PCI-Express slot if it supports x16 lane.

Storage options on the motherboard include six SATA 6 GB/s ports and a single SATA Express port that operates at 10 GB/s. The motherboard supports Raid 0,1,5,10 options and is fully compliant with Intel's RST. There's also a single M.2 Socket 3 slot that can support both SATA and PCI-E based SSDs including NGFF drives.

ASUS has integrated their SupremeFX audio solution on the Z170 Pro gaming motherboard that offers near-lossless audio quality with a signal-to-noise ratio (SNR) of 115dB. The SupremeFX audio is featured on an isolated PCB that is indicated by an illuminated red line shielding and the SupremeFX chip is covered by an EMI protection cover. The PCB uses premium Nichicon audio capacitors which offer fine-quality with natural sound.

I/O on the motherboard includes a PS/2 port, DVI/HDMI/Display Port for display connectivity, LAN (RJ45), 4 USB 3.0 ports, 2 USB 2.0 ports, a single USB 3.1 Type-A port, SPDIF, 7.1 Channel Audio Jack and also a single USB 3.1 Type-C port.

ASUS Z170 Pro Gaming Motherboard Gallery:

Processor	Intel Core i7-5960X Intel Core i7-5930K Intel Core i7-4960X Intel Core i7-3960X Intel Core i7-6700K Intel Core i7-4790K Intel Core i7-4770K Intel Core i7-3770K Intel Core i7-2600K Intel Core i5-4690K Intel Core i5-3570K
Motherboard:	Gigabyte GA-X99-UD7 w/Core i7-5960X Gigabyte GA-X99-UD7 w/Core i7-5930K ASUS X79 Deluxe w/Core i7-4960X Intel DX79SI LGA 2011 w/ Core i7-3960X ASUS Z170 Pro Gaming w/Core i7-6700K Gigabyte GA-Z97X-SOC Force w/Core i7-4790K Gigabyte GA-Z97X-SOC Force w/Core i5-4690K Intel DZ87KLT-75K w/ Core i7-4770K ASRock Z77 Extreme 6 w/ Core i7-3770K ASRock Z77 Extreme 6 w/ Core i7-3570K ASUS Sabertooth P67 w/ Core i7-2600K
Power Supply:	Xigmatek NRP-MC1002 1000 Watt
Hard Disk:	Kingston HyperX 3K 90 GB (OS) Seagate Barracuda 1 TB 7200.12
Memory:	Crucial Ballistix Elite DDR4 2400 MHz (CL11) (4 GB x 4) DDR4 Memory Kit 4 x 4 GB Kingston HyperX 2400 MHz 10th Anniversary Edition Memory Kit (DDR3)
Case:	Cooler Master HAF 932
Video Cards:	GALAX GeForce GTX 970 EXOC BLACK
Cooling Solutions:	Phantek PH-TC14PE Triple Fan
OS:	Windows 8.1 Ultimate 64-bit

Intel Core i7-6700K 4.6 GHz Overclocking

Overclocking on the i7 6700K was pushed to 4.60 GHz with a multiplier of 46 and a BCLK speed of 100 MHz. The overclocking itself was rather easy. Our chip was unable to push to 4.6 GHz without any crashes which is a good impression for Skylake. There are a lot of useful tools in the Z170 Gaming BIOS that can be used to configure on the go overclocking. The chip was supplied a voltage of 1.32V for stable operations.

X264 HD Encode Benchmark

This benchmark measures the encoding performance of the processor. It offers a standardized benchmark as the clip as well as the encoder used is uniform.

Cinebench R15

CINEBENCH is a real-world cross platform test suite that evaluates your computer’s performance capabilities. CINEBENCH is based on MAXON’s award-winning animation software CINEMA 4D, which is used extensively by studios and production houses worldwide for 3D content creation. MAXON software has been used in blockbuster movies such as Iron Man 3, Oblivion, Life of Pi or Prometheus and many more.

Cinebench R11.5

Cinebench is based on Maxon’s Cinema 4D. It is used to compare graphics as well as processor performance. We are using the CPU performance numbers for our comparison.

PCMark 7

PCMark 7 is a complete PC benchmarking solution for Windows 7 and Windows 8. It includes 7 tests combining more than 25 individual workloads covering storage, computation, image and video manipulation, web browsing and gaming. Specifically designed for the full range of PC hardware from netbooks and tablets to notebooks and desktops, PCMark 7 offers complete Windows PC performance testing for home and business use.

POV-Ray

The POV-Ray package includes detailed instructions on using the ray-tracer and creating scenes. Many stunning scenes are included with POV-Ray so you can start creating images immediately when you get the package.

3DMark 11 CPU Performance

DMark 11 makes extensive use of all the new features in DirectX 11 including tessellation, compute shaders and multi-threading. It was released on December 7, 2010. 3DMark 11 includes four Graphics tests – Deep Sea 1 & 2, High Temple 1 & 2 – for measuring GPU performance, a Physics test measuring CPU performance, and a Combined test targeting CPU and GPU performance.

3DMark Vantage CPU Performance

3DMark Vantage is a DirectX 10 video card benchmark test for Windows that is designed to measure your PC’s gaming performance. While the overall benchmark is great, the utility also provides a good indication of the CPU performance.

WinRar

WinRAR is a powerful archive manager. It can backup your data and reduce the size of email attachments, decompress RAR, ZIP and other files downloaded from Internet and create new archives in RAR and ZIP file format.

SuperPI

Super PI is used by many overclockers to test the performance and stability of their computers. In the overclocking community, the standard program provides a benchmark for enthusiasts to compare “world record” pi calculation times and demonstrate their overclocking abilities. The program can also be used to test the stability of a certain overclock speed.

HandBrake

Intel Core i7-6700K – Battlefield 4

Battlefield 4 is the latest installment in the Battlefield franchise. Developed by DICE and published by EA, Battlefield 4 takes multiplayer FPS to the next level unleashing new levels of destruction and the game changing LEVOLUTION. Battlefield 4 is a true next generation experience on the PC rendered with the power of Frostbite 3 which features stunning DirectX 11.1 effects and Tessellation which only a few games dare to match. In addition to the engine, Battlefield 4 would also be the first to support AMD’s latest Mantle API which will leverage the game performance on AMD hardware.

Intel Core i7-6700K – Bioshock: Infinite

Bioshock Infinite, the third title in the franchise developed by Irrational Games takes FPS and story telling to a whole new experience. The game puts us in the boots of Booker who in search of a girl named ‘Elizabeth’ ends up on Columbus,  a bustling metropolis of the early 20th century that floats in the sky. The game uses a modified Unreal Engine making use of DIrectX 11 effects.

Intel Core i7-6700K – Crysis 3 Perfomance

Crysis 3 is the technical and graphical benchmark that most gamers look to for its over-the-top graphical demands. Despite the fact that the game is horribly optimized for most platforms, it is the measure for a lot of people. We went ahead and benchmarked it for the performanceophiles.

Intel Core i7-6700K – Tomb Raider

The Tomb Raider franchise was rebooted this year with the latest title in the long running franchise. The players start off their journey with a younger and under-trained version of Lara who goes off on her first survival action journey.

The Skylake architecture is meant to improve overall system power consumption and add to the efficiency. In the case of the Core i7-6700K, we are looking at a more refined 14nm process which adds more improvements over Broadwell generation of processors. We currently don't have any Broadwell CPU for testing but we know that the Core i7-6700K with a TDP of 91W is a 3W difference compared to the 88W Core i7-4790K. With added performance, we see a slight gain in load consumption but overall, the power consumption remained the same during our testing. When overclocked, the Core i7-6700K did blast past the 400W barrier due to added power and voltage. We used a Phantek's PH-TC14PE cooler to keep the chip cooled under stock and overclocked load and the result was a significant reduction in the temperatures compared to Haswell generation which had been fused with FIVR. The removal of FIVR and a smaller process means that the Skylake architecture is overall more cooler and our chip remained at a steady 32C at idle, 48C (stock load) and 69C (OC load).

Conclusion

We have been reporting Skylake ever since it first appeared on Intel's roadmap. All of the details we gathered pointed out Skylake as being a revolutionary architecture. Now that we have it in our hands, the performance results are finally here and show that the Skylake CPU still doesn't bring the revolution that we all hoped for. In reality, Skylake is more of an evolutionary path to the Core family as it enters its 6th iteration. The Skylake CPU is everything that we hoped for, it is built on a new miroarchitecture, it uses a refined 14nm FinFET process, it has a faster graphics core (although this bit should be discarded as the 6700K is solely aimed at enthusiasts), its a processor built for overclocking enthusiasts but how well do these features translate into actual performance increases?

As seen in our tests, the Core i7-6700K is a faster product compared to Devil's Canyon Core i7-4790K. It leaves behind the Sandy Bridge and Ivy Bridge processors in dust and does so with the same amount of power input. But if we look at the results more closely, we see a nominal 5-10% IPC improvement from 6700K. A year ago, we saw reports claiming a good 20-25% IPC improvement from Skylake but it turns out that Skylake pushed for performance updates in the graphics department rather than the CPU side. The graphics side as indicated in our separate review is a much bigger increase but the CPU side, even with an updated miroarchitecture could not bring any significant improvements to the table. We have yet to see how well Windows 10 and DirectX 12 increases the performance for Skylake CPUs but for now, the results show modest gains as Intel focuses on an annual 5-10% IPC gain. Gone are the times when Intel brought significant increases with the likes of Nehalem and Sandy Bridge.

On the bright side, we have seen so many Core families after Sandy Bridge that the overall IPC improvement per generation lies around 30-35% overall (possibly even more). So users that are still running older PCs now have the opportunity to update to a new platform, especially when Skylake brings with it the Z170 platform upgrades that include faster storage solutions, better IO features and enhanced DDR4 memory support which is really the future upgrade path when it comes to system memory. Motherboards such as the ASUS Z170 Pro actually do offer a lot of value and features at a price close to $170 US. The Core i7-6700K along with its OC features is the obvious choice for enthusiasts as it comes at the same price of $350 US as the Core i7-4790K. Actually, the Skylake flagship retails at just $30 more than the Sandy Bridge flagship which once retailed at $320 US. One can also see that with Haswell still available in retail channels, Intel CPUs have become their own competitors as consumers can spend less on platform upgrades with Haswell than Skylake but the latest Z170 platform has a lot to offer and is much more future proof in the sense you can update to Kaby Lake next year on the same motherboards you purchase with Skylake.

To end this review, I'll say it clearly, Intel Skylake isn't the revolution which we hoped for and one can stop expecting big performance updates from the mainstream family as they aren't getting more cores or even a significant architecture update until Cannonlake and beyond. With silicon becoming more complex as it shrinks down, we should also expect more delays on smaller nodes from Intel. But this review proves that even with all the complexity involved, Intel still managed to deliver a solid product. The Core i7-6700K is faster than 4790K, it's clocked at 4 GHz and has better OC support, it comes with a completely updated Z170 platform and is the first mainstream platform to support DDR4 memory. Sandy Bridge users, the time has finally come to upgrade your battlestations.

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