Core i7-8700K CPU by Intel Review

The Core i7-8700K is a six-core CPU with 12 threads, 3.7 GHz base clock and 4.7 GHz maximum clock, being the highest-end model from Intel’s eighth generation of Core i CPUs. Let’s see how fast is it.
The new eighth generation of Core i7 CPUs from Intel, codename Coffee Lake, was recently launched, among with the new Z370 chipset. In this new generation, the microarchitecture is very similar to the previous one (Kaby Lake), with the same graphics engines, same supported technologies, and the same 14 nm manufacturing technology. The biggest difference is the CPU core count: while, on previous generations, Core i7 CPUs have four cores and eight threads (thanks to the Hyper-Threading technology), Core i5 have four cores and four threads, and the Core i3 have two cores and four threads, on the eighth generation Core i7 CPUs have six cores (and 12 threads), Core i5 processors have six cores (and six threads), and Core i3 CPUs now have four cores (and four threads, as they lose HT technology).
It may be motivated by the launch of AMD Ryzen processors, that bring more cores that Intel conterparts, with similar single core performance. It is clear that the tendency of the industry is offering a higher core count on desktop CPUs, and we can expect programs and games to take advantage of the extra cores on the near future.
It is important to keep in mind that, even if the socket used by the eighth generation CPUs is physically the same used on the sixth and seventh generations (LGA1151), the pin disposition is not exactly the same, allegedly to meet the higher power demand of the new CPUs with more cores. Because of this, sixth and seventh generation CPUs do not work in motherboards designed for the eighth generation ones (that use 300-series chipsets), and vice-versa.
The Core i7-8700K is (so far) the highest-end CPU of this new generation. It has a base clock of 3.7 GHz and a maximum Turbo clock of 4.7 GHz, with 12 MiB of L3 cache. It has a TDP of 95 W and brings with Intel UHD 630 integrated video running up to 1.2 GHz.
Figure 1 shows the Core i7-8700K CPU. It is sold without a cooler.

Figure 1: the Core i7-8700K

In Figure 2 we have the underside of the CPU.

Figure 2: underside of the Core i7-8700K

For our benchmarks, we compared the Core i7-8700K to the the Ryzen 7 1700X (read review here), which is its direct competitor. We also included the Core i7-7700K (review), which is the predecessor of the reviewed CPU.
We used a GeForce GTX 1080 video card on all tests.
Let’s compare the main specs of the reviewed CPUs in the next page.
[nextpage title=”The Reviewed CPUs”]
In the tables below, we compare the main features of the CPUs included in our review.

CPU	Cores	HT/SMT	IGP	Internal Clock	Turbo Clock	Core	Tech.	TDP	Socket	Price
Core i7-8700K	6	Yes	Yes	3.7 GHz	4.7 GHz	Coffee Lake	14 nm	95 W	LGA1151	USD 380
Ryzen 7 1700X	8	Yes	No	3.4 GHz	3.8 GHz	Sumit Ridge	14 nm	95 W	AM4	USD 360
Core i7-7700X	4	Yes	Yes	4.2 GHz	4.5 GHz	Kaby Lake	14 nm	91 W	LGA1151	USD 340

Below you can see the memory configuration for each CPU.

CPU	L2 Cache	L3 Cache	Memory Support	Memory Channels
Core i7-8700K	6 x 256 kiB	12 MiB	Up to DDR4-2666	2
Ryzen 7 1700X	8 x 512 kiB	2 x 8 MiB	Up to DDR4-2666	2
Core i7-7700K	4 x 256 kiB	8 MiB	Up to DDR4-2400	2

[nextpage title=”How We Tested”]During our benchmarking sessions, we used the configuration listed below. Between our benchmarking sessions, the only variable devicand was the CPU being tested, besides the motherboard, which had to be replaced to match the different CPUs.
Hardware Configuration

Motherboard (Coffee Lake): Gigabyte Z370 AORUS Ultra Gaming
Motherboard (Kaby Lake): Gigabyte AORUS Z270X-Gaming 7
Motherboard (AM4): ASRock X370 Taichi
Memory: 16 GiB, two DDR4-3200 8 GiB Geil modules configured at 2666 MHz
Boot drive: Samsung 960 EVO 500 GiB SSD
Video Card: GeForce GTX 1080
Video Monitor: Philips 236VL
Power Supply: Corsair CX600

Operating System Configuration

Windows 10 Home 64-bit
NTFS
Video resolution: 1920 x 1080 60 Hz

Driver Versions

NVIDIA driver version: 387.92

Software Used

Error Margin
We adopted a 4% error margin. Thus, differences below 4% cannot be considered relevant. In other words, products with a performance difference below 4% should be considered as having similar performance.
[nextpage title=”PCMark 10 and 3DMark”]

PCMark 10

PCMark 10 is a benchmarking software that uses real-world applications to measure the computer performance. We ran the standard test, which included applications opening, web browsing, writing, photo editing, video chat, video conversion, and rendering. Let’s see the results.

On the 3DMark 10 benchmark, the Core i7-8700K was 17% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

3DMark

3DMark is a program with a set of several 3D benchmarks. Time Spy runs a DirecX12 simulation; Fire Strike runs a “heavy” DirectX 11 simulation, and Sky Diver also measures DirectX 11 performance, but is aimed on average computers.

On Time Spy, the Core i7-8700K was on a technical tie to the Ryzen 7 1700X and to the Core i7-7700K.

On the Fire Strike benchmark, the Core i7-8700K was 14% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

On the Sky Diver benchmark, the Core i7-8700K was 10% faster than the Ryzen 7 1700X and the Core i7-7700K.

[nextpage title=”Performance in programs”]

Cinebench R15

Cinebench R15 is based on the Cinema 4D software. It is very useful to measure the performance gain obtained by the presence of several processing cores while rendering heavy 3D images. Rendering is an area where a bigger number of cores helps a lot, because usually this kind of software recognize several processors (Cinebench R15, for example, can use up to 256 processing cores).
We ran the CPU benchmark, which renders a complex image using all the processing cores (real and virtual) to speed up the process. The result is given as a score.

On Cinebench R15 CPU benchmark, the Core i7-8700K was 9% slower than the Ryzen 7 1700X, and 42% faster than the Core i7-7700K.

Blender

Blender is a image and movie redering software that uses all the threads of the CPU. We used the program to render a heavy image of a project named Gooseberry Benchmark. The graph below shows the time the CPU used to finish the image, so the less, the better.

On Blender, the Core i7-8700K was 12% faster than the Ryzen 7 1700X, and 41% faster than the Core i7-7700K.

CPU-Z

On its current version, the well-known hardware identification software CPU-Z comes with a benchmarking tool, which measures CPU performance for one core and for all available cores.

On the single thread benchmark, the Core i7-8700K was 20% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

On the multiple thread benchmark, the Core i7-8700K was 14% slower than the Ryzen 7 1700X, and 38% faster than the Core i7-7700K.

Handbrake

Media Espresso is a video conversion program that uses the graphics processing unit of the video engine to speed up the conversion process. We converted a 1 GiB, 1920x1080i, 23,738 kbps, .mov video file to a smaller 320×200, H.264, .MP4 file for viewing on a smartphone. The results below are given in seconds, so the lower the better.

Here the Core i7-8700K performed similarly to the Ryzen 7 1700X, and was 41% faster than the Core i7-7700K.

WinRAR

Another task where the CPU is very demanded is on file compacting. We ran a test compacting a folder with 8 GiB on 6.813 files to a file, using WinRAR 4.2. The graph below shows the time taken on each test.

On WinRAR, the Core i7-8700K was 28% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

V-Ray Benchmark

V-Ray Benchmark is a tool for measuring image rendering performance using the processor and the graphics card. It renders two images, one using the processor (CPU) and one using the video engine (GPU). We ran the benchmark and compared the CPU time on the graphics below.

On V-Ray, the Core i7-8700K was similar to the Ryzen 7 1700X, and was 40% faster than the Core i7-7700K.
[nextpage title=”Gaming Performance”]

Deus Ex: Mankind Divided

Deus Ex: Mankind Divided is an action RPG with FPS elements, launched in August 2016, that uses the Dawn engine, being compatible with DirectX 12. We tested it using the benchmark included in the game, with DirectX 12 enabled, Full HD, and graphic options as “medium”.
The results below are expressed in frames per second.

On this game, the Core i7-8700K was 39% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

Dirt Rally

Dirt Rally is an off-road racing game released in April 2015, using Ego engine. To measure performance using this game, we ran the performance test included in the game, in 1920 x 1080 (Full HD) resolution and image quality configured as “medium” and MSAA off.

The results below are expressed in frames per second (fps).
In this game, the Core i7-8700K was 38% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

Grand Theft Auto V

Grand Theft Auto V, or simply GTA V, is an open-world action game released for PCs in April of 2015, using the RAGE engine. In order to measure the performance on this game, we ran the performance test of the game, measuring the framerate with FRAPS. We ran GTA V at Full HD, with all image quality set as “normal” and MSAA off.

The results below are expressed in frames per second.

On GTA V, the Core i7-8700K was 13% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.

Hitman

Hitman is an action/stealth game, launched in March 2016, that uses a DirectX 12 compatible version of the Glacier 2 engine. To measure performance in this game, we ran the benchmark in it, measuring the framerate with FRAPS. We ran this game with DirectX 12 enabled, with image quality set as “high”.
The results below, in Full HD and 4K, are expressed in frames per second.On Hitman, the Core i7-8700K was 41% faster than the Ryzen 7 1700X, and 9% slowe than the Core i7-7700K.

Rise of the Tomb Rider

Rise of the Tomb Rider is an adventure/action game launched in January of 2016, based on Foundation engine. In order to measure the performance using this game, we ran the benchmark included on it, using Full HD resolution and graphics quality set to “medium”.
The results below are expressed in frames per second.Also on Rise of the Tomb Rider, the Core i7-8700K was 25% faster than the Ryzen 7 1700X, and performed similarly to the Core i7-7700K.
[nextpage title=”Overclocking”]
The Intel CPUs with “K” suffix have unlocked clock multiplier, which means you can overclocking it just by changing its multiplier, as long as the motherboard has this feature.
We were able to configure the CPU to run stable at 5.0 GHz (100 MHz reference clock and x50 multiplier), with the original voltages. It may be possible to reach higher frequencies if you “play” with the available adjusts, as long as you have a good power supply, motherboard, and cooling system.
It is also good to keep in mind that the overclock capability depends on pure luck, since two CPUs of same model can reach different maximum clocks.
[nextpage title=”Conclusions”]
To be honest, the results of our tests bring no surprise, and we have to admit that Intel did exactly what it must have done on the Core i7 lineup. When the AMD Ryzen 7 family was launched, it couldn’t reach for the gaming performance of the Core i7 models on the market at the time (Core i7-7700K and Core i7-7700), but it was superior in tasks that take advantage of their eight cores and 16 threads, like video and image rendering.
So, the logical path for Intel not to stay behind was to increase the number of cores on their flagship CPUs, and it was exactly what it did. With two cores (and therefore four threads) more, the Core i7-8700K performed much like its predecessor Core i7-7700K in games, but attained a big performance gain in tasks like image rendering, reaching (and, in some cases, surpassing) the performance of the Ryzen 7 1700X on this kind of task.
There are some additional details to say. Even if the maximum clock of the Core i7-8700K is higher than the Core i7-7700K’s, its base clock is lower, in order to mantain a similar TDP even with 50% more cores. So, under heavy loads, the Core i7-8700K uses a lower clock rate than the Core i7-7700K; that’s why its performance is lower in some tests.
On the other hand, the overclocking potential of the Core i7-8700K is excellent (as long as it is well cooled). For heavy applications, on the hands of an enthusiast user, it can run at 5.0 GHz on all cores, which promises a high performance for any kind of application.
So, we can say Intel take a hit with the Core i7-8700K: it makes a high-end CPU for both gaming and professional applications.