Conclusion
AMD’s competitive architecture, disruptive pricing, and class-leading core counts continues to turn heads. Intel responded to the Threadripper family by introducing Skylake-X-based CPUs for less money per core than we've ever seen before. Up until now, though, it showed no interest in affecting that metric with its mainstream desktop chips. This changes with Coffee Lake, which employs the same underlying architecture as Kaby Lake, but adds execution cores and cache. Improved Turbo Boost bins also help maintain performance in lightly-threaded tasks.
Intel says that its Core i7-8700K is the company's best gaming processor ever. So, we use a geometric mean of 99th percentile frame times, a good indicator of smoothness, converted into an FPS measurement, to gauge the veracity of this bold claim across our suite. Five of the games we test were released in 2016, and five are older (2014/2015). Extra cores could enable more performance as software evolves, so we also include a chart with newer games that thoroughly utilize available host processing resources. We also have price-to-performance charts that get split up to include both the price of the processor and extra platform costs. For the models that don't come with a bundled cooler, we add an extra $25 for a basic heat sink. We also add $20 if overclocking requires a more expensive motherboard (as is the case for Z370).
Despite a few missteps, Core i7-8700K lives up to Intel’s claims. While it doesn't beat the -7700K by a massive margin, the Coffee Lake flagship does deliver better performance in stock and overclocked form. Of course, adding a Z370 motherboard and competent cooler knocks you over the $400 mark, so be ready to pay for that privilege.
Value-seekers have to be asking if Core i7-8700K's price tag is even worth paying, then. After all, you can get Ryzen 7 1800X-class performance out of an overclocked Ryzen 7 1700 for $300 or less. But based on our matrix, Coffee Lake gives you the best performance (furthest to the right) without getting too crazy on price. We're naturally wondering how Core i5-8600K will fare. For now, though, Core i7-8700K is the gaming CPU to own.
Whereas Kaby Lake tends to fall behind Ryzen once we jump out of the games and start looking at rendering/encoding workloads, Coffee Lake's extra cores, higher clock rates, and overclocking headroom help close that gap. Applications previously notorious for going AMD's way are now more hotly contested.
Unfortunately, you will have to buy a new Z370-based motherboard to support Core i7-8700K. Coffee Lake necessarily breaks compatibility with the not-altogether-old Z270 chipset for higher memory data rates and improved power to the CPU's package. And of course, the Z-series platform controller hub is a requisite if you want access to unlocked ratio multipliers. Lower-end B- and H-series chipsets are coming, but not until next year.
We're also disappointed that Core i7-8700K still utilizes thermal paste between its die and heat spreader. Whereas this was a significant issue during our Skylake-X evaluation, though, it's not as problematic on a 95W CPU. You can easily stave off throttling with a heat sink and fan, or dial in a respectable overclock under a closed-loop liquid cooler.
Intel has its 10nm Cannon Lake processors coming in the second half of 2018, and AMD has a Ryzen refresh cycle coming next year. Knowing this, should you upgrade now or wait for the next wave of hardware? Due to the iterative nature of most updates, we rarely recommend jumping forward one, or even two generations. However, if you routinely find yourself running productivity workloads that might be served well by Core i7-8700K's extra cores, we could see replacing a quad-core chip with six cores. Gamers interested in maximum performance or streaming also stand to benefit, though in a world of single-GPU graphics configurations, you'd be hard-pressed to bottleneck an overclocked -7700K with even a GeForce GTX 1080 Ti (particularly at the high resolutions it's meant to drive).
It's an exciting year to be an enthusiast. Intel obviously planned to beef up its line-up years back, but we can thank AMD for the accelerated timeline and competitive pricing. Competition truly is a wonderful thing.
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