Intel Skylake-X and Kaby Lake-X CPUs, Motherboards, and Coolers: Your Complete Guide

HIGHLIGHTS

• Intel's new Core X-series family includes a confusing variety of models
• The Skylake-X and Kaby Lake-X processors are very different
• Not all CPU and motherboard combinations deliver the same experiences

For nearly ten years, Intel's Core i3, i5, and i7 brands have held strong in the PC and laptop space. Everyone immediately gets the idea of a hierarchy, with Core i3 at the entry-level and Core i7 at the top end. You don't necessarily need to know that you get two cores and HyperThreading with an i3, and four cores without HyperThreading if you choose an i5. You don't need to know clock speeds, cache sizes, or manufacturing processes - what matters is that when all capabilities are taken into consideration, moving from a lower number to a higher one gives you an incremental boost in performance. Within each generation, all chips work on the same motherboards, use the same kind of RAM, and have the same architectural advantages - with one key exception.

At the very high end, there are Intel's High-End Desktop (HEDT) models, awkwardly clubbed into the Core i7 family. These are often called Extreme Edition chips, though not all of their model numbers actually have that suffix. These CPUs need a different platform altogether, lack integrated graphics, and are based on a souped-up version of the previous-generation architecture. For example, the Core i7 6950X was codenamed Broadwell-E, which is a derivative of the 5th-gen Broadwell architecture, whereas the rest of the 6th generation was codenamed Skylake.

While you can still only get up to four CPU cores with the top mainstream Core i7 after all these years, Intel has pushed out six-, eight-, and ten-core models under the HEDT Core i7 umbrella over the years, and has charged enormous amounts of money for them. In the beginning, it was rumoured that Intel would use the name Core i9 for these products since they were so obviously different from the rest of the lineup, but that did not come to pass. They were called Core i7 even though they didn't really fit that name.

Adding to the confusion, HEDT generations have been launching later and later each year. In our review of the 10-core Intel Core i9-6950X, we pointed out how the much cheaper quad-core Core i7-6700K outclassed it in some tests. Broadwell-E, technically based on the 5th-gen architecture, launched at around the same time as the 7th-gen Kaby Lake lineup.

Now, in 2017, Intel also needs to fend off new competition from a resurgent AMD, which is now selling octa-core Ryzen 7 CPUs and gleefully pointing out how they outperform Intel's latest and greatest while costing a fraction of the price. With Ryzen Threadripper shipping soon, clearly, Intel has a lot of cleaning up to do.Introducing the Intel Core X-series

Finally, we have a Core i9 brand to distinguish HEDT CPUs from the mainstream. Unfortunately, there are a few new layers of complication to replace the old ones. For starters, all new Core i9 models fall under what Intel is calling its new Core X-series, which also includes a few Core i7s and one Core i5 model. Core X clearly isn't about superior performance. Core X also mixes two Intel architectures, Skylake-X and Kaby Lake-X (Intel swapped out the -E suffix, but the idea is the same). The two CPU lines are referred to collectively by the code name Basin Falls.

The new Core i5-7640X and Core i7-7740X are based on Kaby Lake-X, while the other two Core i7s and all Core-i9 models are based on Skylake-X. All Core-X CPUs use the new LGA2066 socket and X299 platform controller - which means that not only is the Core i7 family just as fragmented as before, the Core i5 family is too. Core i9 encompasses a few new parts and a few renamed ones, and Intel hasn't improved its segmentation at all in the bargain. The only advantage of this is that the company gets to leapfrog the generation-lag issue and use a shiny new name against AMD's Threadripper when it comes out.

As for the differences between Skylake-X and Kaby Lake-X, things can get quite confusing, but we'll try breaking it all down. Skylake-X is what we'd usually consider the "extreme" CPUs for any generation There are seven models in all, starting with the six-core i7-7800X and going up to the top-of-the-line 18-core Core i9-7980XE. Models with up to 10 cores are already available, and the rest are set to begin shipping between August and October this year.