Notebookcheck

Coffee Lake: i7-8700K and i5-8400 Review

Silvio Werner, Klaus Hinum (translated by Martin Jungowski), 10/06/2017

With the new Coffee Lake CPUs, Intel brings more than four physical cores to end-user consumer computing for the first time in its history. Regardless of whether or not you want to consider this a reaction to AMD's Ryzen, Coffee Lake manages to combine high clock speeds with more cores than before and has earned our recommendation.

Coffee Lake

For the original German article, see here.

One of the many selling points of Intel’s eighth-generation Core processors named Coffee Lake is a 15% higher SysMark performance. However, we wouldn’t consider this to be its main selling point. Instead, that honor would go to the major restructuring that took place within Intel’s portfolio: the i7-8700(K), i7-8600K and i5-8400 are all equipped with six physical cores - a first for Intel, whose end-user processor line-up topped out at four cores until now. In addition to two extra cores, single-threaded performance is supposed to remain persistently high thanks to consistently high clock speeds.

Despite the fact that the underlying architecture remained mostly identical to its Kaby Lake predecessor, the new processors are incompatible with already existing Kaby Lake motherboards. Once again, Intel’s tick-tock model that once promised a new architecture roughly every three years does not apply anymore: Coffee Lake is the fourth generation of 14 nm microprocessors. The integrated graphics card has also remained almost identical to its predecessor despite the change of name. While the Intel UHD Graphics 630 now supports DisplayPort 1.2 as well as HDMI 2.0, the 50 MHz boost in frequency is negligible.

Model Cores - Threads Base Frequency Turbo Boost L3-Cache TDP Street Price, (List Price)
Core i7-8700K 6-12 3.7 GHz 4.7 GHz 12 MB 95 Watts 359 Dollars
Core i7-8700 6-12 3.2 GHz 4.6 GHz 12 MB 65 Watts 303 Dollars
Core i5-8600K 6-6 3.6 GHz 4.3 GHz 9 MB 95 Watts 257 Dollars
Core i5-8400 6-6 2.8 GHz 4.0 GHz 9 MB 65 Watts 182 Dollars
Core i3-8350K 4-4 4.0 GHz - 6 MB 91 Watts 168 Dollars
Core i3-8100 4-4 3.6 GHz - 6 MB 65 Watts 117 Dollars
Core i7-7740X 4-8 4.3 GHz 4.5 GHz 8 MB 112 Watts 350 Euros
Core i7-7700K 4-8 4.2 GHz 4.5 GHz 8 MB 95 Watts 330 Euros
Ryzen R7 1700X 8-16 3.4 GHz 3.8/3.5 GHz 16 MB 95 Watts 360 Euros
Ryzen R5 1600 6-12 3.2 GHz 3.6 GHz 16 MB 65 Watts 210 Euros

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Core i7-8700K and i5-8400

Photo: Intel
Photo: Intel

Both Coffee Lake processors reviewed by us, the i7-8700K and the i5-8400, feature a total of six physical cores but differ in the number of simultaneous threads, cache size, clock speed, and obviously price: the i7-8700K is twice as expensive as the i5-8400.

Priced similarly as the Ryzen R7 1700X, the i7-8700K offers fewer cores but a higher clock speed than its main competitor. In-house competition is composed of the i7-7700K albeit with less cores and a lower clock speed. The i5-8400 is priced similarly to the Ryzen R5 1600, and although the latter offers a total of six cores and 12 threads its maximum turbo boost frequency is slightly lower.

Synthetic Benchmarks

Cinebench R15

This particular synthetic benchmark allows for a quick and easy quantification of raw computing power by measuring the time it takes to render a scene consisting of more than 2,000 objects and 300,000 polygons. Given that it supports multiple threads, the benchmark benefits not only from high clock speeds but also the number of cores and threads available. The single-thread test benefits greatly from high clock speeds and cache.

In theory, it is feasible that some processors are better suited for Cinebench’s computation requirements but from our experience this particular benchmark is very well suited for a quick comparison of theoretical maximum processing power.

What surprised us most was the Core i7-8700K’s single-thread performance - it equaled the i7-7700K’s excellent high score. AMD’s Ryzen CPUs fall at least 15% behind in this test.

Even the i5-8400 managed to outperform the Ryzen R7 1800X in this test, albeit only slightly. Its lead on the similarly priced 1700X is more pronounced yet still within acceptable margins. However, the gap between it and both Core i7-X700K models is enormous.

As expected, the i7-8700K outperformed its in-house competitors in the multithread benchmark with ease but was in turn overtaken by the slightly cheaper yet 9% faster Ryzen R7 1700X. Compared to its own predecessor, the i7-7700K, the difference was a staggering 45% - which pretty much reflects the difference in cores between these two.

The Core i5-8400 we will have to file under also-ran. Despite its two additional cores it fails to best the Core i7-7700K and is around 16% slower than its main competitor, the Ryzen R5 1600.

Cinebench R15
CPU Single 64Bit
Intel Core i7-7740X
195 Points ∼100% +17%
Intel Core i7-7700K
194 Points ∼99% +16%
Intel Core i7-8700K
194 Points ∼99% +16%
Intel Core i9-7900X
192.74 Points ∼99% +15%
Intel Core i5-7600K
191 Points ∼98% +14%
Intel Core i5-8400
167 Points ∼86%
AMD Ryzen 7 1800X
164 Points ∼84% -2%
AMD Ryzen 7 1700X
157 Points ∼81% -6%
AMD Ryzen 5 1500X
157 Points ∼81% -6%
Intel Core i7-7700HQ
149 Points ∼76% -11%
AMD Ryzen 7 1700
147.65 Points ∼76% -12%
AMD Ryzen 5 1600
147 Points ∼75% -12%
AMD Ryzen 5 1400
134.5 (min: 133.01) Points ∼69% -19%
CPU Multi 64Bit
Intel Core i9-7900X
2148 (min: 2133.11) Points ∼100% +128%
AMD Ryzen 7 1800X
1647 Points ∼77% +75%
AMD Ryzen 7 1700X
1557 Points ∼72% +65%
Intel Core i7-8700K
1422 Points ∼66% +51%
AMD Ryzen 7 1700
1417.69 (min: 1413.38) Points ∼66% +51%
AMD Ryzen 5 1600
1125 Points ∼52% +20%
Intel Core i7-7740X
988 Points ∼46% +5%
Intel Core i7-7700K
984 Points ∼46% +5%
Intel Core i5-8400
941 (min: 921.89) Points ∼44%
AMD Ryzen 5 1500X
817.5 Points ∼38% -13%
Intel Core i7-7700HQ
738 Points ∼34% -22%
AMD Ryzen 5 1400
692 (min: 676.26) Points ∼32% -26%
Intel Core i5-7600K
688 Points ∼32% -27%

TrueCrypt

TrueCrypt uses various encryption algorithms in order to determine processing power. Unlike Cinebench R15, this benchmark is much closer to real-world usage scenarios even though the implications regarding everyday performance are rather minor. The algorithms used in this benchmark are Serpent, Twofish, and Rijndael (more commonly known as AES).

It profits mainly from high clock speeds on all cores, which is why the i7-8700K manages to beat its own predecessor by a whopping 46%. That said, AMD’s Ryzen R7 1700X is yet another 10% faster. The cheaper i5-8400 is only around 10% slower than the roughly $100 more expensive i7-7700K, but like before the comparatively priced Ryzen R5 1600 is slightly faster once again.

Performance Rating
Intel Core i9-7900X
100 pt ∼100%
AMD Ryzen 7 1800X
76.5 pt ∼77%
AMD Ryzen 7 1700X
72.8 pt ∼73%
Intel Core i7-8700K
66.4 pt ∼66%
AMD Ryzen 5 1600
52.5 pt ∼53%
AMD Ryzen 5 1600
48.5 pt ∼49%
Intel Core i7-7740X
45.7 pt ∼46%
Intel Core i7-7700K
45.4 pt ∼45%
Intel Core i5-8400
40.8 pt ∼41%
AMD Ryzen 5 1500X
38.2 pt ∼38%
AMD Ryzen 5 1400
33 pt ∼33%
Intel Core i5-7600K
30.1 pt ∼30%
TrueCrypt
Serpent Mean 100MB
Intel Core i9-7900X
1.2 GB/s ∼100% +140%
AMD Ryzen 7 1800X
0.945 GB/s ∼79% +89%
AMD Ryzen 7 1700X
0.898 GB/s ∼75% +80%
Intel Core i7-8700K
0.796 GB/s ∼66% +59%
AMD Ryzen 5 1600
0.655 GB/s ∼55% +31%
AMD Ryzen 5 1600
0.649 GB/s ∼54% +30%
Intel Core i7-7700K
0.554 GB/s ∼46% +11%
Intel Core i7-7740X
0.551 GB/s ∼46% +10%
Intel Core i5-8400
0.5 GB/s ∼42%
AMD Ryzen 5 1500X
0.465 GB/s ∼39% -7%
AMD Ryzen 5 1400
0.41 GB/s ∼34% -18%
Intel Core i5-7600K
0.367 GB/s ∼31% -27%
Twofish Mean 100MB
Intel Core i9-7900X
2.1 GB/s ∼100% +154%
AMD Ryzen 7 1800X
1.5 GB/s ∼71% +81%
AMD Ryzen 7 1700X
1.4 GB/s ∼67% +69%
Intel Core i7-8700K
1.4 GB/s ∼67% +69%
AMD Ryzen 5 1600
1 GB/s ∼48% +21%
AMD Ryzen 5 1600
1 GB/s ∼48% +21%
Intel Core i7-7740X
0.944 GB/s ∼45% +14%
Intel Core i7-7700K
0.939 GB/s ∼45% +14%
Intel Core i5-8400
0.827 GB/s ∼39%
AMD Ryzen 5 1500X
0.744 GB/s ∼35% -10%
AMD Ryzen 5 1400
0.647 GB/s ∼31% -22%
Intel Core i5-7600K
0.611 GB/s ∼29% -26%
AES Mean 100MB
Intel Core i9-7900X
12.1 GB/s ∼100% +142%
AMD Ryzen 7 1800X
9.6 GB/s ∼79% +92%
AMD Ryzen 7 1700X
9.3 GB/s ∼77% +86%
Intel Core i7-8700K
8 GB/s ∼66% +60%
AMD Ryzen 5 1600
6.7 GB/s ∼55% +34%
Intel Core i7-7740X
5.6 GB/s ∼46% +12%
Intel Core i7-7700K
5.5 GB/s ∼45% +10%
AMD Ryzen 5 1600
5.3 GB/s ∼44% +6%
Intel Core i5-8400
5 GB/s ∼41%
AMD Ryzen 5 1500X
4.9 GB/s ∼40% -2%
AMD Ryzen 5 1400
4.1 GB/s ∼34% -18%
Intel Core i5-7600K
3.7 GB/s ∼31% -26%

wPrime

wPrime uses Newton’s method for estimating functions in order to calculate square roots, verifying the results by squaring them and comparing the result with the original number. This synthetic benchmark uses all available cores.

As before, the Ryzen R7 1700X manages to easily outperform both Coffee Lake contenders by 9% (i7-8700K) and 76% (i5-8400), respectively. While the latter did score higher than the Ryzen R5 1500X in this benchmark, it was nowhere near the Ryzen R5 1600’s level of performance. In return, the i7-7700K was only around 11% faster.

wPrime 2.0x
1024m
Intel Core i5-7600K
259.5 s * ∼100% -35%
AMD Ryzen 5 1400
237.3 s * ∼91% -24%
AMD Ryzen 5 1500X
210.6 s * ∼81% -10%
Intel Core i5-8400
191.8 s * ∼74%
Intel Core i7-7700K
169.8 s * ∼65% +11%
Intel Core i7-7740X
167.2 s * ∼64% +13%
AMD Ryzen 5 1600
149 s * ∼57% +22%
Intel Core i7-8700K
118.9 s * ∼46% +38%
AMD Ryzen 7 1700X
109 s * ∼42% +43%
AMD Ryzen 7 1800X
103 s * ∼40% +46%
Intel Core i9-7900X
76 s * ∼29% +60%
32m
Intel Core i5-7600K
8.3 s * ∼100% -34%
AMD Ryzen 5 1400
7.8 s * ∼94% -26%
AMD Ryzen 5 1500X
6.9 s * ∼83% -11%
Intel Core i5-8400
6.2 s * ∼75%
Intel Core i7-7700K
5.5 s * ∼66% +11%
Intel Core i7-7740X
5.4 s * ∼65% +13%
AMD Ryzen 5 1600
5.2 s * ∼63% +16%
Intel Core i7-8700K
4.96 s * ∼60% +20%
AMD Ryzen 7 1700X
4 s * ∼48% +35%
AMD Ryzen 7 1800X
3.8 s * ∼46% +39%
Intel Core i9-7900X
2.91 s * ∼35% +53%

* ... smaller is better

Other Synthetic Benchmarks

As usual, we would like to present you with additional synthetic benchmark results without commenting on them individually. The WinRAR benchmark results have to be taken with a grain of salt since they performed very oddly on Ryzen systems.

Geekbench 4.0
64 Bit Multi-Core Score
Intel Core i9-7900X
27533 Points ∼100% +41%
Intel Core i7-8700K
23230 (min: 23142) Points ∼84% +19%
AMD Ryzen 7 1800X
22009 Points ∼80% +13%
AMD Ryzen 7 1700X
21038 Points ∼76% +8%
AMD Ryzen 7 1700
19784 Points ∼72% +1%
Intel Core i5-8400
19500 Points ∼71%
Intel Core i7-7740X
18383 Points ∼67% -6%
AMD Ryzen 5 1600
17937 Points ∼65% -8%
Intel Core i7-7700K
17800 Points ∼65% -9%
Intel Core i5-7600K
15030 Points ∼55% -23%
AMD Ryzen 5 1500X
14463 Points ∼53% -26%
Intel Core i7-7700HQ
14026 Points ∼51% -28%
AMD Ryzen 5 1400
12785 Points ∼46% -34%
64 Bit Single-Core Score
Intel Core i7-8700K
5738 (min: 5724) Points ∼100% +15%
Intel Core i7-7740X
5619 Points ∼98% +12%
Intel Core i7-7700K
5480 Points ∼96% +10%
Intel Core i5-7600K
5225 Points ∼91% +5%
Intel Core i5-8400
4996 Points ∼87%
Intel Core i9-7900X
4987 Points ∼87% 0%
AMD Ryzen 7 1800X
4499 Points ∼78% -10%
AMD Ryzen 7 1700X
4333 Points ∼76% -13%
Intel Core i7-7700HQ
4321 Points ∼75% -14%
AMD Ryzen 7 1700
4179 Points ∼73% -16%
AMD Ryzen 5 1500X
4149 Points ∼72% -17%
AMD Ryzen 5 1600
4130 Points ∼72% -17%
AMD Ryzen 5 1400
3885 Points ∼68% -22%
WinRAR - Result
Intel Core i7-8700K
7120 KB/s ∼100% +38%
Intel Core i7-7740X
6417 KB/s ∼90% +24%
Intel Core i9-7900X
5918 KB/s ∼83% +14%
Intel Core i7-7700K
5823 KB/s ∼82% +13%
Intel Core i5-8400
5173 KB/s ∼73%
AMD Ryzen 7 1800X
4120 KB/s ∼58% -20%
AMD Ryzen 7 1700X
3999 KB/s ∼56% -23%
AMD Ryzen 5 1500X
3910 KB/s ∼55% -24%
AMD Ryzen 5 1600
3687 KB/s ∼52% -29%
Intel Core i5-7600K
3570 KB/s ∼50% -31%
AMD Ryzen 5 1400
3147 KB/s ∼44% -39%
X264 HD Benchmark 4.0
Pass 2
Intel Core i9-7900X
121 fps ∼100% +97%
AMD Ryzen 7 1800X
95 fps ∼79% +55%
AMD Ryzen 7 1700X
90.6 fps ∼75% +48%
Intel Core i7-8700K
87.4 fps ∼72% +42%
AMD Ryzen 5 1600
68.7 fps ∼57% +12%
Intel Core i7-7740X
61.7 (min: 61.6) fps ∼51% 0%
Intel Core i7-7700K
61.6 fps ∼51% 0%
Intel Core i5-8400
61.4 fps ∼51%
AMD Ryzen 5 1500X
49.5 fps ∼41% -19%
Intel Core i5-7600K
46.2 fps ∼38% -25%
AMD Ryzen 5 1400
43.4 fps ∼36% -29%
Pass 1
Intel Core i7-7740X
233.6 (min: 231.9) fps ∼100% +4%
Intel Core i7-8700K
232 (min: 229) fps ∼99% +4%
Intel Core i7-7700K
230 fps ∼98% +3%
Intel Core i5-8400
223.8 fps ∼96%
Intel Core i5-7600K
223 fps ∼95% 0%
Intel Core i9-7900X
217 fps ∼93% -3%
AMD Ryzen 7 1800X
195 fps ∼83% -13%
AMD Ryzen 7 1700X
186 fps ∼80% -17%
AMD Ryzen 5 1600
177 fps ∼76% -21%
AMD Ryzen 5 1500X
177 fps ∼76% -21%
AMD Ryzen 5 1400
154 fps ∼66% -31%
PCMark 8
Work Score Accelerated v2
Intel Core i9-7900X
5325 Points ∼100%
Intel Core i7-7700HQ
5234 Points ∼98%
Intel Core i7-7700K
5167 Points ∼97%
Intel Core i7-7740X
4977 Points ∼93%
Intel Core i7-8700K
4821 Points ∼91%
AMD Ryzen 5 1500X
4557 Points ∼86%
AMD Ryzen 7 1800X
4511 Points ∼85%
AMD Ryzen 7 1700X
4487 Points ∼84%
AMD Ryzen 5 1600
4431 Points ∼83%
AMD Ryzen 7 1700
4402 Points ∼83%
AMD Ryzen 5 1400
4401 Points ∼83%
Home Score Accelerated v2
Intel Core i7-7740X
5347 Points ∼100%
Intel Core i9-7900X
5239 Points ∼98%
Intel Core i7-7700K
5042 Points ∼94%
Intel Core i5-7600K
4749 Points ∼89%
AMD Ryzen 7 1800X
4746 Points ∼89%
Intel Core i7-8700K
4648 Points ∼87%
AMD Ryzen 5 1500X
4647 Points ∼87%
AMD Ryzen 7 1700X
4613 Points ∼86%
AMD Ryzen 7 1700
4485 Points ∼84%
AMD Ryzen 5 1600
4437 Points ∼83%
AMD Ryzen 5 1400
4346 Points ∼81%
Intel Core i7-7700HQ
4069 Points ∼76%
3DMark
2560x1440 Time Spy CPU
Intel Core i9-7900X
10131 Points ∼100% +84%
AMD Ryzen 7 1800X
8252 Points ∼81% +50%
AMD Ryzen 7 1700X
7806 Points ∼77% +42%
AMD Ryzen 7 1700X
7806 Points ∼77% +42%
AMD Ryzen 7 1700
7415 Points ∼73% +35%
Intel Core i7-7740X
5632 Points ∼56% +2%
AMD Ryzen 5 1600
5542 Points ∼55% +1%
Intel Core i5-8400
5509 Points ∼54%
Intel Core i7-7700K
5490 Points ∼54% 0%
Intel Core i7-7700HQ
4189 Points ∼41% -24%
Intel Core i5-7600K
4152 Points ∼41% -25%
AMD Ryzen 5 1500X
4067 Points ∼40% -26%
AMD Ryzen 5 1400
3700 Points ∼37% -33%
1920x1080 Fire Strike Physics
Intel Core i9-7900X
22626 Points ∼100% +83%
Intel Core i7-8700K
19358 Points ∼86% +57%
AMD Ryzen 7 1800X
18915 Points ∼84% +53%
AMD Ryzen 7 1700X
18407 Points ∼81% +49%
AMD Ryzen 7 1700
16830 Points ∼74% +36%
AMD Ryzen 5 1600
15818 Points ∼70% +28%
Intel Core i7-7740X
14432 Points ∼64% +17%
Intel Core i7-7700K
14325 Points ∼63% +16%
Intel Core i5-8400
12346 Points ∼55%
AMD Ryzen 5 1400
10848 Points ∼48% -12%
Intel Core i7-7700HQ
10455 Points ∼46% -15%
Intel Core i5-7600K
9292 Points ∼41% -25%
3DMark 11 - 1280x720 Performance Physics
Intel Core i9-7900X
15260 Points ∼100%
AMD Ryzen 7 1800X
14150 Points ∼93%
AMD Ryzen 7 1700
13124 Points ∼86%
Intel Core i7-7740X
12322 Points ∼81%
Intel Core i7-7700K
12026 Points ∼79%
AMD Ryzen 5 1600
11164 Points ∼73%
AMD Ryzen 5 1500X
9566 Points ∼63%
Intel Core i7-7700HQ
9462 Points ∼62%
AMD Ryzen 5 1400
8177 Points ∼54%
3DMark 06 - CPU - ---
Intel Core i9-7900X
12678 Points ∼100%
Intel Core i7-8700K
11599 Points ∼91%
Intel Core i7-7740X
10229 Points ∼81%
Intel Core i7-7700K
10156 Points ∼80%
AMD Ryzen 7 1700
8940 Points ∼71%
Intel Core i5-7600K
8532 Points ∼67%
AMD Ryzen 5 1600
8222 Points ∼65%
Intel Core i7-7700HQ
7761 Points ∼61%
AMD Ryzen 5 1500X
7403 Points ∼58%
AMD Ryzen 5 1400
6599 Points ∼52%

Preliminary Recap

In synthetic benchmarks, the i7-8700K performed exceptionally well. Its single-core performance is comparable to the i7-7700K (which means that it outperforms the entire Ryzen line-up) yet it doesn’t fall too far behind in multi-core tests. The i7-8700K is thus a very decent combination of high single- and multi-core performance, a mix that AMD has failed to deliver so far.

In single-core benchmarks, the i5-8400 managed to best every single Ryzen CPU, but it failed to keep up with the Core i7-7700K despite its two extra cores due to its lower clock speeds and its lack of Hyper-Threading.

Gaming Benchmarks

Test System

Gigabyte Aorus Z370. Photo: Gigabyte
Gigabyte Aorus Z370. Photo: Gigabyte

Powerful CPUs demand powerful GPUs, and we’ve chose a GeForce GTX 1080 Ti Founders Edition - one of the fastest currently available graphics cards - which we installed in an Aorus Z370 Ultra Gaming motherboard by Gigabyte accompanied by 16 GB of dual-channel DDR4-3000 RAM.

Further details regarding the specific motherboards for each of the other processors in this comparison can be found in the respective reviews thereof.

In order to determine the real effect of CPU performance on video games we had to eliminate the GPU as determining factor, and we were consequently forced to choose a rather unrealistic gaming scenario: low resolution and minimum details to achieve maximum CPU load.

Frame Rates

Average frame rates in For Honor were excellent for both Coffee Lake contestants, and they easily outperformed all available Ryzen CPUs. The i7-8700K was almost exactly as fast as the i7-7700K while the i5-8400 was 14% slower.

In The Witcher 3, our most frequently used and therefore also most important gaming benchmark, both Coffee Lake processors easily beat the entire Ryzen line-up at 1024x768 and low details once again. In this test, even the i5-8400 was at least as fast as the fastest Ryzen consumer CPU, the R7 1800X.

The i7-8700K achieved spectacular results in The Witcher 3. It was only slightly slower than the more than $1,000 expensive Intel Core i9-7900X, around 8% faster than the i7-7700K, and roughly 23% faster than the Ryzen 7 1800X.

For Honor
3840x2160 High Preset AA:T AF:8x
Intel Core i7-7700K
79 (min: 46) fps ∼100% +2%
Intel Core i7-7740X
79 (min: 63) fps ∼100% +2%
AMD Ryzen 7 1700
78 (min: 63) fps ∼99% +1%
Intel Core i9-7900X
78 (min: 62) fps ∼99% +1%
Intel Core i5-7600K
77.9 (min: 23) fps ∼99% 0%
AMD Ryzen 5 1500X
77.8 (min: 63) fps ∼98% 0%
AMD Ryzen 5 1400
77.6 (min: 63) fps ∼98% 0%
Intel Core i5-8400
77.6 (min: 60) fps ∼98%
Intel Core i7-8700K
77.3 (min: 63) fps ∼98% 0%
AMD Ryzen 5 1600
77.1 (min: 62) fps ∼98% -1%
AMD Ryzen 7 1800X
77 (min: 62) fps ∼97% -1%
Intel Core i7-5960X
76 (min: 30) fps ∼96% -2%
1280x720 Low Preset
Intel Core i7-7740X
347 (min: 240) fps ∼100% +21%
Intel Core i7-7700K
333 (min: 184) fps ∼96% +16%
Intel Core i7-8700K
328 (min: 184) fps ∼95% +15%
Intel Core i5-8400
286 (min: 141) fps ∼82%
AMD Ryzen 5 1500X
271 (min: 193) fps ∼78% -5%
Intel Core i5-7600K
263 (min: 17) fps ∼76% -8%
AMD Ryzen 5 1600
250 (min: 187) fps ∼72% -13%
AMD Ryzen 5 1400
233 (min: 145) fps ∼67% -19%
AMD Ryzen 7 1800X
230 (min: 187) fps ∼66% -20%
Intel Core i7-5960X
224 (min: 168) fps ∼65% -22%
AMD Ryzen 7 1700
208 (min: 159) fps ∼60% -27%
Intel Core i9-7900X
155 (min: 129) fps ∼45% -46%
Farming Simulator 17 - 3840x2160 High Preset AA:2xMS AF:2x
Intel Core i7-7740X
213 (min: 195) fps ∼100% +11%
Intel Core i5-7600K
205 (min: 191) fps ∼96% +7%
Intel Core i7-7700K
204 (min: 188) fps ∼96% +6%
Intel Core i9-7900X
201 (min: 186) fps ∼94% +5%
AMD Ryzen 5 1500X
195 (min: 188) fps ∼92% +2%
Intel Core i7-8700K
194 (min: 179) fps ∼91% +1%
Intel Core i5-8400
192 (min: 178) fps ∼90%
Intel Core i7-5960X
191 (min: 175) fps ∼90% -1%
AMD Ryzen 7 1800X
191 (min: 180) fps ∼90% -1%
AMD Ryzen 5 1600
188 (min: 177) fps ∼88% -2%
AMD Ryzen 7 1700
181 (min: 172) fps ∼85% -6%
AMD Ryzen 5 1400
170 (min: 164) fps ∼80% -11%
The Witcher 3
1920x1080 Ultra Graphics & Postprocessing (HBAO+)
Intel Core i7-7740X
102 (min: 87) fps ∼100% +1%
Intel Core i7-8700K
102 (min: 86) fps ∼100% +1%
Intel Core i5-8400
101 (min: 87) fps ∼99%
Intel Core i7-7700K
100 (min: 86) fps ∼98% -1%
AMD Ryzen 7 1700
98 fps ∼96% -3%
AMD Ryzen 7 1800X
97 (min: 83) fps ∼95% -4%
Intel Core i9-7900X
97 (min: 80) fps ∼95% -4%
AMD Ryzen 5 1500X
96.4 (min: 84) fps ∼95% -5%
AMD Ryzen 5 1400
96.3 (min: 83) fps ∼94% -5%
AMD Ryzen 5 1600
95 (min: 80) fps ∼93% -6%
1024x768 Low Graphics & Postprocessing
Intel Core i9-7900X
349 (min: 260) fps ∼100% +15%
Intel Core i7-8700K
338 (min: 307) fps ∼97% +12%
Intel Core i7-7740X
327 (min: 258) fps ∼94% +8%
Intel Core i7-7700K
313 (min: 284) fps ∼90% +3%
Intel Core i5-8400
303 (min: 277) fps ∼87%
AMD Ryzen 7 1800X
297 (min: 267) fps ∼85% -2%
AMD Ryzen 7 1700
274 (min: 243) fps ∼79% -10%
AMD Ryzen 5 1600
254 (min: 237) fps ∼73% -16%
AMD Ryzen 5 1500X
250 (min: 226) fps ∼72% -17%
AMD Ryzen 5 1400
225 (min: 202) fps ∼64% -26%

Frame Time Analysis

In our frame time analysis, the Core i7-8700K presented itself as an excellent choice for gamers. There are almost no spikes and outliers, and its base frame rate is better than the Ryzen 7 1700X’s or the Core i7-7700K’s.

While the i5-8400 offered lower frame rates overall, it was very consistent. It is worth noting that both the i7-8700K and the i5-8400 have a comparatively high number of minor frame time deviations, yet major deviations are much less common than on Ryzen processors. Given that the latter have a higher overall average frame time the difference is even more pronounced due to the higher margins.

i7-8700K frame times
i7-8700K frame times
i5-8400 frame times
i5-8400 frame times
Model Core i7-8700K Core i5-8400 Core i7-7700K Core i7-7740X Ryzen R7 1800X Ryzen R7 1700 Ryzen R5 1600
Frame time (Median, in µs) 2,953 3,269 3,169 3,032 3,525 3,823 3,840
min. 20 % deviation 1.963% 3.789% 1.555% 1.891% 0.473% 1.129% 1.104%
min. 50 % deviation 0.186% 0.263% 0.187% 0.266% 0.141% 0.213% 0.176%
min. 100 % deviation 0.056% 0.052% 0.049% 0.091% 0.068% 0.066% 0.047%
min. 300 % deviation 0.010% 0.000% 0.000% 0.032% 0.018% 0.053% 0.020%

Energy Efficiency

Power consumption is measured at the outlet and is therefore the sum of all components. Accordingly, the significance in regard to microprocessor-specific power consumption is rather limited.

The upside to this is that we can present you with a much more realistic assessment of total power draw as a combination of motherboard, graphics card, and RAM. While conclusive statements regarding the energy efficiency of one specific processor are impossible to make in this scenario, we can at least draw indirect deductions from our measurements.

That said, both Coffee Lake processors were pretty low-key when idle but much less efficient per watt in Cinebench R15 than others.

power consumption (idle)
power consumption (idle)
energy efficiency per watt
energy efficiency per watt

Verdict

Photo: Intel
Photo: Intel

Whether or not we have to thank AMD for Intel’s quick turnaround on the availability of six-core consumer-grade CPUs we will never know for sure. However, it became very clear to us that the Core i7-8700K hits the sweet spot of multi-core performance almost on a par with Ryzen and a very high single-core performance to boot. Accordingly, it fares very well in video games and is therefore an extremely versatile microprocessor for professionals and consumers alike. The same can be said about the i5-8400: its gaming performance is exceptional when compared to AMD’s Ryzen, and it is therefore definitely highly recommendable for gamers.

Additional Benchmarks

Clevo, a well-known notebook distributor, has published additional Cinebench R15 results of various CPUs that we did not have at our disposal at the time of writing. According to that list, the i7-8700 scored 1,208/192 points (multi/single), the i5-8600K scored 1013/183 points, and the i3-8100 scored 590/154 points. This means that in single-thread performance, even the i3-8100 is almost as fast as AMD’s Ryzen R7 1800X. On the other hand, in multi-core it would be slower than the Ryzen 5 1400.

Review Samples

The review samples for this review have been provided by Intel (CPU) and AMD (Ryzen CPUs, Asus motherboard, memory, Noctua cooler). The motherboard was provided by Gigabyte.

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> Notebook / Laptop Reviews and News > Reviews > Coffee Lake: i7-8700K and i5-8400 Review
Silvio Werner, Klaus Hinum, 2017-10- 6 (Update: 2017-10- 8)