Intel Core i7-6700K Skylake Overclocked To 5.2 GHz With Air Cooling at 1.35V
Intel's Skylake processors are going to hit the market in a couple of weeks and we have seen several samples already rolling out in the wild which have been tested by a few Chinese sites. The Core i7-6700K is going to be the flagship processor of the lineup and we have seen some preliminary performance numbers in benchmarks obtained from a test rig that use premature drivers and an early BIOS version that wasn't fully configured to drive Skylake processors. The latest report on the Core i7-6700K shows that overclocking on the unlocked chips will be impressive than ever.
Image Credits: HKEPC
Intel Core i7-6700K Overclocked to 5.2 GHz Clock Speed on Air Cooling
HKEPC is the first site to report an overclock on the flagship Skylake processor. Their Chief-Reporter, Lam Chu-Kui was able to obtain an impressive clock speed of 5.2 GHz on the Skylake processor but there's more to this overclock than just a bump in clock frequencies which we will get to in a second. First, it should be mentioned that the upcoming Skylake-S Unlocked processors which include the Core i7-6700K and Core i5-6600K are the first processors in the lineup that launch on 5th August and will be coupled with several Z170 motherboards that will be available on the same date (actually some are already available on retail). These chips will be the successor of the Devil's Canyon based Core i7-4790K and Core i5-4690K.
Taking a quick glance a the flagship Core i7-6700K CPU, we are looking at a quad core design with eight threads which shows a multi-threaded design. The chip features 8 MB of L3 cache and has clock speeds maintained at 4.0 GHz base and 4.2 GHz boost clock. The chip can support DDR4 2133 MHz memory and DDR3L 1600 MHz memory. The processor features the Intel 530 graphics chip with 24 execution units, clock speeds of 300 MHz base an 1150 MHz boost and full support for DirectX 12 API. The overall specs aren't much different than the Devil's Canyon Core i7-4790K which had same core configuration, 4.0 GHz base and 4.4 GHz boost but a slower iGPU (HD 4600) with 20 EUs and 1250 MHz boost clock. The main changes have been featured as micro-architecture improvements which leads to gain in IPC (Instructions per clock cycle) and efficiency (performance per watt) on a 14nm process.
Intel Core i7-4790K Slide [Showcasing improved thermal/power management systems]
With Devil's Canyon, Intel gave Haswell two updates. One was a refocused power delivery and management system to tone down the heat generation on the core. It was further improved by a NGPTIM (Next Generation Polymer-based Thermal Interface Material) which gave a better contact surface to the die with the heat-spreader to effectively transfer heat to the IHS and then dissipate it to a active-cooling heatsink. This did help to reduce temperatures to some extent but the addition of voltage regulation unit on the chip itself meant that the problem still existed when higher voltages were configured during overclocking sessions. Sure the chip could reach high clocks on LN2 but most overclockers had voltage pushing past 1.5 - 1.52V on a 5.1-5.2 GHz overclock.
The overclock shown today is a 1200 MHz (1.2 GHz) clock speed improvement over the reference clock speed of 4.0 GHz on the Core i7-6700K. Not only that, it was achieved with air cooling with a voltage supply of just 1.35V. The temperatures were said to be under limits and overclocking on Skylake is considered to be more fun than Broadwell processors which are a feast to overclock. If the overclock turns out stable and final samples are also able to obtain similar overclocks, then it will be a fine day for the enthusiast world.
Intel Core i7-6700K WPRIME 32M Benchmark @ 5.0 GHz (1.312V):