Intel Core i9 7900X Skylake-X & Core i7 7740X Kaby Lake-X review: rushed release raises the bar

Intel reinforces lead and introduces most unnecessary CPU ever



Intel allows high-end desktops to achieve much higher performances by introducing Skylake-X and Kaby Lake-X. This is certainly good news for content creators, who could use the higher performance for 3D-rendering, video editing or other demanding, creative workloads. Nevertheless there are some ifs and buts before we can start cheering, which takes us to a famous old movie…

The good…

There is no reason to doubt the performance of Skylake-X. Although it is rather expensive, the 10-core Core i9 7900X is by far the fastest processor in multi-threaded workloads at the moment. Whereas the previous Broadwell-E high-end desktop processors still had a big backlog in the single-threaded workloads compared with the less expensive mid-range Socket 1151 models, Skylake-X does not have a bad performance in such benchmarks.

Compared with AMD, the 8- and 10-core models of Intel are considerably more expensive than the 8-core AMD Ryzen CPUs, but they are also clearly faster, in multi- as well as in single-threaded applications. Speaking of prices, now you can purchase a 10-core CPU (Core i9 7900X) at a lower price than an Intel 8-core CPU (Core i7 6900K). Similarly you can purchase an 8-core variant (Core i7 7820X) at a price that thus far would not be able to get you Intel’s fastest 6-core (Core i7 6850K).

Another positive factor: the Intel X299 chipset has 30 flexible I/O-lanes which makes it an ideal basis for high-end PCs. Most Socket 2066 motherboards offer space for multiple fast M.2 SSDs and are also entirely up-to-date in other regards.

Finally, it is good news that Intel has announced to bring 12-core, 14-core 16-core and even 18-core CPUs to desktops. This is clearly an answer to AMD’s plans with ThreadRipper. But whatever the reason is, we can only applaud the kinds of steps Intel is taking. (However, you might want to start saving…)

The bad…

Not to state the obvious, but there is always the law of diminishing returns with high-end processors. The 10-core Core i9 7900X almost costs twice as much as the 8-core Core i7 7820X, but the price / performance ratio is not in proportion (assuming the 7820X is a tiny bit faster than Intel’s existing 8-core CPUs). Just as a car worth 100,000 dollars will not be twice as fast or good as a car worth 50,000 dollars, the same can be said for CPUs with roughly two zeroes less. Nonetheless, someone who renders, edits videos and does other multi-threaded tasks daily would love to have one.

However, it is a completely different story for gamers. In many cases games do not tax the cores enough to activate Turbo Mode. Because of this, the Core i9 often performs worse than the i7 7700K. Perhaps Intel will make some optimizations, but it seems primarily a disadvantage of the fact that these are server processors. Those are simply not invented with gaming in mind as their primary use.

What is unfortunate, is the fact that you need to buy a 999 dollars top model to be able to use the 44 PCI-Express 3.0 lanes. For most people this is not an issue, because this many lanes solely have an advantage in multi-GPU configurations. Combining two graphics cards is easier (both 16 lanes instead of 8) and combining three or four graphics cards with the cheaper CPUs is not even possible in a good way.

Besides that, we will repeat it once more: VROC (Virtual RAID of CPU) is an amazing technology, but in our opinion the high costs that are associated with it immediately makes it uninteresting for consumers.

… and the ugly

We can be positive about the Skylake-X for content creators and others who benefit from the computing power of 8 or 10 cores, however in Kaby Lake-X’s case we are anything but. As expected, the Core i7 7740X is merely slightly faster than its counterpart, the Socket 1151 7700X. However, you have to combine them with a much more expensive motherboard. As a result of a limited number of memory channels and PCI-Express lanes much of its functionality is lost. In addition, the convenient QuickSync functionality of Kaby Lake-X cannot be used.

What’s more is that soon (if we believe the rumours) the Coffee Lake generation will bring 6-core CPUs to Intel’s mid-range platform. In this case, we can only draw one conclusion regarding Kaby Lake-X: do not purchase it. At this moment, for the vast majority of gamers and other demanding users a CPU with four to six cores is the sweetspot, but the future Coffee Lake and Ryzen seem to be much more logical options than the expensive socket 2066-platform.

So who is the real winner this generation? Let it be clear – without the return of AMD on the market for high-end CPUs, this launch would have been different. Intel is being forced to increase the clock speed of their CPUs, which causes great repercussions on the power usage of the chips. Moreover, they are forced to lower their price. Focusing on the computing power, Intel will be at the top of the charts for now, although with less finesse as before.

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