Intel Core i7 8700K Review Leaks Out – The Flagship Coffee Lake 6 Core CPU Is Faster Than The Core i7-7700K and Core i7-7800X at The Same Clocks

Hassan Mujtaba

There have been two embargo breaks in the last 24 hours, first Intel had to let reviewers publish the 8th Generation desktop processor details two weeks earlier because the information was out already and now, one of the top Chinese tech sites, Expreview, has leaked out the entire review of the upcoming Coffee Lake flagship processor, the Core i7-8700K.

Intel Core i7-8700K Review Leaks Out - The Fastest Processor For Gaming, 7% Faster Than The Core i7-7700K In Gaming at Same Clocks

So the review tests the Intel Core i7-8700K in several scenarios against the Core i7-7700K and the Core i7-7800X. The thing to note is that the Core i7-8700K is designed for the mainstream platform but since the core count has been bumped up to 6 on the flagship, the comparison with the HEDT Core i7-7800X makes a lot of sense. Comparison with the Core i7-7700K is also worth noting as the Core i7-8700K replaces the older flagship mainstream CPU at just about the same price while being better in every possible way. Before we point out the benchmarks, lets take a look at the specs for the Core i7-8700K.

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Intel Core i7-8700K – The Coffee Lake Flagship With 6 Cores and 4.3 GHz Boost Across All Cores

The Intel Core i7-8700K will be the flagship processor of the lineup. It will feature 6 cores and 12 threads. The chip will be compatible with the LGA 1151 socket on the Z370 chipset only. The chip will be Intel’s first hexa core product and will be based on the 14nm process node.


In terms of clock speeds, we are looking at a 3.7 GHz base frequency which boosts up to 4.3 GHz (6 core) and 4.7 GHz (1 core). These clocks are really impressive so we can expect much faster gaming performance on Coffee Lake parts than the current generation of CPUs. The chip is fully unlocked allowing for overclocking and comes with a TDP of 95W. There’s 12 MB of L3 cache on board along with a GT2 tier iGPU. The chip supports DDR4-2666 MHz memory (native) and up to 4400 MHz+ (OC). The Intel Core i7-8700K will cost $359 US at launch. You can check out the full Intel 8th Gen desktop processor coverage over here.

Intel Core i5-8600K – The Gamer Aimed Hexa Core With Overclocking Capability and 4.3 GHz Boost

The Intel Core i5-8600K is the second unlocked chip in the lineup and features a hexa core design. We have learned that the Intel Core i5 series will stick with 6 cores but they will not feature a multi-threaded design. The chip probably features 9 MB of L3 cache while being supported on the LGA 1151 socket.


In terms of clock speeds, we are looking at 3.5 GHz base, 4.2 GHz (6 core), 4.3 GHz (1 core) boost clocks. The chip will feature a TDP of 95W and the pricing will be set at $257 US which is just a few bucks over $242 US Price of the Core i5-7600K making it a great option for gamers who want some extra cores inside their rigs. You can check out the full Intel 8th Gen desktop processor coverage over here.

Intel Coffee Lake 8th Gen Desktop Core Lineup:

CPU NameIntel Core i3-8100Intel Core i3-8350KIntel Core i5-8400Intel Core i5-8600KIntel Core i7-8700Intel Core i7-8700KIntel Core i7-8086K
CPU FamilyCoffee Lake-SCoffee Lake-SCoffee Lake-SCoffee Lake-SCoffee Lake-SCoffee Lake-SCoffee Lake-S
CPU Process14nm14nm14nm14nm14nm14nm14nm
CPU Cores4466666
CPU Threads4466121212
Base Clock3.60 GHz4.00 GHz2.80 GHz3.60 GHz 3.20 GHz3.70 GHz4.00 GHz
Boost Clock (Max)N/AN/A4.00 GHz4.30 GHz4.60 GHz4.70 GHz5.00 GHz
Boost Clock (6 Core)N/AN/A3.50 GHz4.40 GHz4.20 GHz4.30 GHz4.30 GHz
L2 Cache1 MB (256 KB per Core)1 MB (256 KB per Core)1.5 MB (256 KB per Core)1.5 MB (256 KB per Core)1.5 MB (256 KB per Core)1.5 MB (256 KB per Core)1.5 MB (256 KB per Core)
L3 Cache6 MB6 MB9 MB9 MB12 MB12 MB12 MB
Overclocking SupportNoYesNoYesNoYesYes
Socket SupportLGA 1151LGA 1151LGA 1151LGA 1151LGA 1151LGA 1151LGA 1151
Price$117 US$168 US$182 US$257 US$303 US$359 US$429 US

The Intel Core i7-8700K vs Intel Core i7-7700K vs Intel Core i7-7800X CPU Benchmarks

Like mentioned before, there are several scenarios used for testing the processors. We are looking at stock, overclocked and clock for clock comparisons between the three different processors. Now bear in mind that all three CPUs are basically built on the same architectural DNA. The 7700K has the Kaby Lake architecture which is a refreshed version of Skylake that came before it. Similarly, the Core i7-7800X is built on the Skylake architecture but adds some HEDT features such as Quad channel memory, higher PCIe lanes and the new Mesh interconnect. The Core i7-8700K is based on by far the most optimized version of the 14nm process node known as 14nm++ but the underlying architecture is same as Skylake and Kaby Lake.

The Intel Core i7-8700K has several frequency ranges on the amount of functional cores. They are as follows:

  • Intel Core i7-8700K 6 Core Clock Speed - 4.3 GHz
  • Intel Core i7-8700K 4 Core Clock Speed - 4.4 GHz
  • Intel Core i7-8700K 3 Core Clock Speed - 4.5 GHz
  • Intel Core i7-8700K 2 Core Clock Speed - 4.6 GHz
  • Intel Core i7-8700K 1 Core Clock Speed - 4.7 GHz

First up, the benchmarks compare all three processors at the stock configured clocks and scores resulted in tests indicate that the Core i7-8700K is 1.67% faster than the Core i7-7700K in Single and 42.49% faster in multi-threaded tests. The Core i7-8700K is up to 11% faster than the Core i7-7800X but HEDT offers more than 20% performance uplift in multi-threaded application tests due to quad channel memory and AVX-512 instruction set giving it a good lead in Sandra 2017 bench suite that largely affects the overall score.

Intel Core i7-8700K CPU Synthetic Application and Office Benchmarks Test at Stock Clocks


Intel Core i7-8700K CPU Gaming Performance Benchmarks at Stock Clocks

In office application tests, the Core i7-8700K is 8% faster than the Core i7-7700K and 7% faster than the Core i7-7800X. The most interesting results that users are willing to see is the gaming workload performance and here, the Core i7-8700K is 2% faster than the Core i7-7700K and 5% faster than a Core i7-7800X clocked at stock frequencies. Games that love a high number of fast cores take a big advantage but we were told that performance will further increase as new BIOSs roll out for boards in the coming week.

Intel Core i7-8700K CPU Synthetic Application and Office Benchmarks Test at Same Clocks


Intel Core i7-8700K CPU Gaming Performance Benchmarks at Same Clocks

But what happens when all three chips are clocked at the same frequency? At 4.5 GHz, the benchmark results show that all three processors deliver the same single-threaded performance but the multi-threading performance goes up to 45% over the Core i7-7700K in general benchmarks. When tested in games, the similar clocked processors deliver very different results. The Core i7-8700K leads across all benchmarks with a 7-10% gain over the Core i7-7700K and Core i7-7800X.

These leaked benchmarks and the review overall shows an early look at the Core i7-8700K CPU performance numbers and is looking really great for new PC builders, especially gamers requiring more cores on Intel's mainstream platform. There are some key metrics yet to be detailed such as the power consumption numbers, overclocking and temperature. We will have our review out on the official launch date of 5th October so stay tuned.

[UPDATE] - Just a few hours after the first review got leaked, this second one has popped up from PCOnline who have done a more detailed comparison of the Core i7-8700K and Core i5-8600K in several benchmarks against the older 7th Gen Kaby Lake and AMD Ryzen processors. The results in all tests are posted below:

Intel Core i7-8700K and Core i5-8600K CPU Benchmarks


Intel Core i7-8700K and Core i5-8600K Gaming Benchmarks

Note: Games are in the following order: (Civilization VI, Tomb Raider, Ashes of The Singularity, Ghost Recon Wildlands).


Intel Core i7-8700K and Core i5-8600K Power Consumption and Thermal Tests

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