Intel Core i7 8700K / i5 8600K / i5 8400 'Coffee Lake' review: affordable six cores!

More cores for the same price!



Have we already said that competition is good for the processor market this year? Intel takes, enforced by AMD or not, the biggest step in performance since the Nehalem-generation. Back then, in 2008, we saw 6-core Intel-processors for the first time in the high-end platform. Now, in 2017, they are finally available in the mid-range platform.

The architecture of Coffee Lake remains unchanged - clock for clock the CPUs are just as fast as Skylake and Kaby Lake. Thanks to the slightly higher clockspeeds the performance in games and single-threaded workloads are a small improvement over what we expected of Intel, while we see a huge performance gain in multi-threaded tasks thanks to the extra cores. 

Surely we can thank AMD for this: the hot breath of the Ryzen-processors caused Intel to finally introduce more cores for the mainstream platform. The performance differences that we see now in comparison with the previous generation would probably not have happened had AMD not made their comeback. 

The extra speed that Intel put behind the release of Coffee Lake does lead to some imperfections here and there. For example the Z370-chipset is identical to Z270 in terms of functionality, where the still absent USB 3.1-support is becoming a farce. Of course it is a shame that owners of a Z170- or Z270-motherboard need a new board in order to use the Coffee Lake CPUs, but due to the increase in power consumption this is understandable, at least for the i5s and i7s. Aside from that we find it unfortunate that Intel still uses poorly conductive thermal paste between the die and the heatspreader, but in terms of temperatures this is much less of an issue here than with the high-end Skylake-X CPUs. 

The cheapest model that we tested today, the i5 8400, is exactly as expensive as its predecessor in contrast with the other two CPUs. The six cores mean that it is an attractive option for those that work a lot with multi-threaded software, but do not want to overclock. For this processor AMD still has a strong competitor in the form of the Ryzen 5 1600, that is overclockable and also features SMT. 

The Core i5 8600K is probably the ultimate CPU for gaming. Six cores is now truly the sweetspot for this purpose - there are a few games that prefer six 'real' cores over a 6-core with SMT or HyperThreading. The gaming performance of the i5 8600K is excellent and often slightly higher compared with the Kaby Lakes, which only further increases the gap with AMD here. Aside from the fact that this Core i5 has high stock clockspeeds, it is also excellent for overclocking. 

The Core i7 8700K adds HyperThreading to the featureset of the i5 8600K, which results in a performance boost- especially in multi-threaded applications. In synthetic benchmarks such as Cinebench the Ryzen 7 1800X remains the fastest, but in real world benchmarks such as Adobe Photoshop and Premiere Pro and also video-encoding, the Core i7 turns out to be at least as fast. The high turbo speed of 4.7 GHz also results in excellent performance in single-threaded tasks. All things considered, with the i7 8700K Intel combines excellent single- and multi-threaded performance into one product. 

Is AMD Ryzen now irrelevant? Definitely not in our opinion. The Ryzens are often available at a good price and for Coffee Lake there are only rather expensive Z370-boards available at the moment. The price-conscious buyer that is looking for good performance in software that scales well with multiple cores still has an interesting option in the AMD processors. 

Nevertheless Intel took a big step forwards with the Coffee Lake-generation. This generation gives the most reason to upgrade in a long time: even more so when you are still using Sandy or Ivy Bridge, but even coming from a recent Haswell or Skylake processor the upgrade is worth it in our opinion - provided that you can actually benefit from the extra performance. In short, this year has been an absolute party for the hardware enthusiasts and Coffee Lake is an after party that is worth sticking around for.

To conclude, out of all the introduced processors the new quad-core Core i3s are on paper the most interesting ones - we will try to obtain such a processor as soon as possible. Keep an eye on Hardware.Info for a review!

Intel Core i5 8600K


three products discussed in this review

  Product Lowest price

Intel Core i5 8400 Boxed

Socket 1151, 2.8 GHz, 6 cores, 65 W, 14 nm, Integrated graphics

Specifications Test results Reviews Prices


Avg. £262.76
7 shops, 5x stock

Intel Core i5 8600K Boxed

Socket 1151, 3.6 GHz, 6 cores, 95 W, 14 nm, Integrated graphics

Specifications Test results Reviews Prices


Avg. £265.11
8 shops, 7x stock

Intel Core i7 8700K Boxed

Socket 1151, 3.7 GHz, 6 cores, 95 W, 14 nm, Integrated graphics

Specifications Test results Reviews Prices


Avg. £420.94
8 shops, 7x stock

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