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Intel Core i7-8700K and i5-8400 Coffee Lake CPU Review

By Steven Bassiri from Oct 5, 2017 @ 8:01 CDT
TweakTown Rating: 93%Manufacturer: Intel

This is where you can fast forward to the final section of the review, and get a quick recap and points on the Core i7-8700K and i5-8400.


What's Hot


50% More Cores: Intel's 7700K was one of the best gaming CPUs because it showed off Intel's leading per core performance and high-frequency turbo bins, which many games take full advantage of. The 8700K takes those two things and adds in two more cores, which is a big deal for anyone who is core strapped but needs the high-frequency turbo and per core performance. With two extra cores, it should now be easier to multitask while gaming on Intel CPUs. We also see that Intel's 6-core CPU is obviously very strong against the 6-core CPU of their competitor, but there is a big price difference between the two.



Strong Overclocking: We didn't expect to reach 5.0Ghz with 6 cores, without an AVX offset, and without delidding. However, we were able to hit that mark, and it was quite easy to do. The CPU uses Intel's refined 14nm++ process, so we have to give credit where it's due.


4.7GHz Single Core: A 4.7GHz Turbo is one of the highest we have ever seen from Intel. It makes the 8700K the performance king when it comes to single core performance, beating out the 7700K and 7740X in CINEBENCH R15 at stock. The high single core Turbo also makes the 8700K very versatile; more multi-threaded and single-threaded performance than its predecessor.


Minimal Price Increase: A few months ago, before preliminary price leaks, people thought Intel would increase the price of the 8700K closer to the $400 or $500 mark. No one really expected Intel to launch the 8700K so close to the price of the 7700K, but they did.


What's Not


Need to Buy a New Motherboard: You are going to have to buy a Z370 motherboard at launch if you want to play with the new 8th generation chips. For many people who have 7700Ks or other 6th or 7th generation core processors, this is frustrating since the CPU fits, and it's the same socket.


Thermal Interface Material: We don't really know the real reason Intel isn't using solder based thermal interface material between the CPU die and the integrated heat spreader. It could be one of many reasons; cost, Intel trying to use conflict-free materials, die size, etc. However, the fact of the matter is that it doesn't use solder based TIM, and we are going to see a lot of people delid their CPUs.



Final Thoughts


The i7-8700K and i5-8400 are a step in the right direction. That direction is the move towards more cores, and what the industry needed was for both sides to release mainstream 6-core parts. While 6-core parts have existed for many generations, they have typically been priced quite high, but now you can buy affordable 6-core CPUs from both Intel and AMD. That means we will see more optimizations in software for higher core count CPUs, as more people will have them. I would think that in the coming months and years, games will be updated to utilize more cores. The 8700K is a solid CPU, and a great replacement for the 7700K, as 4-core and 8-threads have become a bit outdated since AMD's Ryzen launch.




Intel was able to not only increase single threaded performance, which was what kept the 7700K above water for a long time, but they also increased core count by 50% without increasing power consumption more than 10%. That's a solid accomplishment. We shouldn't turn a blind eye to the $182 i5-8400 either, its performance is solid, and it's currently the least expensive 6-core CPU on the market.


While we haven't seen much regarding microarchitecture changes to the CPU or iGPU, we have seen frequency increases, and core count boosts (core IA), and we welcome these enhancements to Intel's mainstream lineup. The 7700K isn't the king of the hill anymore, so let's make way for the more robust 8700K.

Product Summary Breakdown

TweakTown award
Overall TweakTown Rating93%

The Bottom Line: Taking the crown from the 7700K in both multi-threaded and single-core performance, the 8700K is an excellent replacement for a very popular CPU. On the flip side, the i5-8400 is positioned as the least expensive way to get six real cores into your home computer.

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