Intel Coffee Lake i7-8700K & i5-8400 Review

by Michael "SKYMTL" Hoenig     |     October 4, 2017

It seems like ever since the launch of AMDís Ryzen and the subsequent introduction of Threadripper, Intel has been on roll. If you have doubts about that, I'll invite you to discuss them in our forum comment thread for this article. While there were some who rightfully accused Team Blue of sitting on their laurels while their competition toiled with a completely uncompetitive architecture, things have rapidly changed. In the key high end desktop (HEDT) market the Skylake-X processors were initially met head on by AMDís 19xx generation and it was only the introduction of ultra expensive 16 and 18 core variants that saved Intelís bacon. Meanwhile the Ryzen 7, Ryzen 5 and Ryzen 3 series ended up stealing Kaby Lakeís thunder in lower price points since they were able to offer more threads alongside reasonably high clock speeds at a lower cost.

This is where Coffee Lake gets factored into the equation since in my original Ryzen 7 analysis I mentioned some concerns. While AMDís new architecture obviously blew Skylake out of the water in most instances and competed well against Kaby Lake, Intel was on the cusp of launching Coffee Lake and that could cause a speed bump for the plucky Ryzen CPUs. Kaby Lake-X failed to make a dent in their leadership but that could all change.

Make no mistake about it; Coffee Lake isnít a response to Ryzen but rather a natural continuation of Intelís strategy for 2017 and beyond. Remember that roadmaps and architectures take years to bring to fruition and the course plotted for these new processors was set in stone long before AMD surged back into the larger picture. That means Intel had to rely on frequency adaptability over architectural revisions to insure they remained in the driverís seatÖand thatís exactly what happened. They have been able to successfully combine more cores, higher frequencies and better efficiency into a single generation without moving beyond their tried and tested 14nm manufacturing process.

Before getting too far into this, I need to delve a bit deeper into that 14nm process since it has proven to be both a liability and asset for Intel. When it was launched back in 2014 with Broadwell, the 14nm 3D tri-gate process was revolutionary since it allowed those processors to incorporate more transistors into an exceedingly compact die area. Intel has since evolved 14nm to the point where they are actually able to increase physical core counts without blowing past the low TDP values Core-series processors are known for. This so-called 14nm++ process has also been optimized for improved frequencies and also includes a few additional optimizations as well.

All of this leads to a very interesting lineup indeed, headlined by the $360USD i7-8700K. This 6 core, 12 thread CPU may not have the core counts to compete with the $400 Ryzen 7 1700X and $330 Ryzen 7 1700 but those are the processors Intel is going after. Not only does the 8700K split the price different between the two but it also operates at substantially higher core speeds (both Base and Boost) while also featuring a very similar TDP range. Add to that Intelís new Smart Cache technology which we detailed in the Kaby Lake-X performance review and this may indeed be a winning formula.

The i7-8700 is another interesting addition to the Coffee Lake lineup but one that will largely appeal to those who donítí plan on overclocking or system integrators who are looking to maximize their bang to buck ratio. It has the exact same specifications as the 8700K but utilizes a bit lower frequencies to justify its price reduction of $54. Donít forget that Intel is also sticking to their K-series overclocking mentality where only certain K-branded SKUs receive unlocked multipliers. That means the i7-8700 canít be overclocked, making it perfect for prebuilt systems.

Moving ever so slightly down-market brings me to the i5-8600K, a processor that will likely be the darling of this particular lineup. You see, unlike its quad core predecessor this little guy receives six native cores without Hyper Threading, an unlocked multiplier and a price of $260. That makes it a prime competitor for AMDís very popular Ryzen 5 1600X and once again the higher clock speeds of Coffee Lake alongside that 9MB of so-called Smart Cache could be a key differentiating factor.

Personally I think the next step down in the Coffee Lake product stack is the most intriguing and possibly the best positioned to put the screws to AMD. The i5-8400 is a somewhat oddly named CPU since its 6-core, 6-thread layout is identical to that of the 8600K but the key differentiator is in the frequencies. This CPU operates at a Base speed of just 2.8GHz but I never experienced it hitting less than 3.1GHz, even in the most strenuous of conditions. Could this make it a perfect competitor against the Ryzen 5 1500X? That depends on how it aligns against a 4 core, 8 thread competitor that can be overclocked, unlike this SKU which has its capabilities locked behind a wall. Want that extra headroom? Intel is asking you to pony up the $80 for their 8600K.

At a price thatís within spitting distance of the i5-8400 thereís Intelís quad core, unlocked i3-8350K. It may not have a Turbo ratio but if history is any indication, the i3 processors have historically offered some insane bang for buck ratios in gaming. This one likely wonít be any different but some may feel like the native 6-core layout of the 8400 may be money well spent despite the 8350Kís overclocking capabilities.

Finally, at the Coffee Lake lineupís trailing edge thereís the i3-8100 which costs just $115 and boasts a native quad core layout. Again we are seeing the ďoverclocking taxĒ implemented in a pretty big way since the $55 separating it and the 8350K accounts for just 400Mhz and an unlocked multiplier.

With these processors in place, there seems to be lot of space left over for additional entrants into the Coffee Lake lineup. Thereís also to concern of mission creep into Kaby Lake-X territory. With the X299 platform housing some relatively affordable options of its own (remember, the i7-7740X costs some $20 less than the i7-8700K), how will these two very similar options sleep in the same bed? That remains to be seen but as we make our way through this article, it will become obvious that Intel intends for each respective chipsetís inherent capabilities (and limitations) to be a determining factor in any purchase.

A number of pretty significant questions have been swirling around Coffee Lake since its inception and subsequent soft launch late last month. In short Intel is trying to capitalize upon their manufacturing process leadership by enhancing clock speeds so theyíre further afield from AMDís while also adding more physical cores across their entire product stack. Will this approach of trying to do more with less really work? Well, thatís what this review is trying to find out.

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