The Intel Kaby Lake-X i7-7740X Review

Author: SKYMTL
Date: June 18, 2017
Product Name: i7-7740X
Part Number: i7-7740X
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Explaining the Unexplainable; Say Hello to Kaby Lake-X

If that past was any indication, our introduction to Intelís new HEDT lineup would have started and stopped on the previous page. But this is 2017 and sowing confusion among your potential clients seems like the ďinĒ thing to do among companies. Enter Kaby Lake-X, a series of processors that are being shoehorned into this launch in truly odd fashion and with capabilities that are nothing if not bewildering on a high end platform. You may have noticed that the features I mentioned on the last page were listed as ďSkylake-XĒ and thatís because none of those improvements are making their way to Kaby Lake-X chips.

The reason for my slightly salty introduction to Kaby Lake-X is because adding them into an X299 system will cause all manner of changes to the platformís core feature sets. Even though these CPUs still utilize the LGA 2066 socket, they only have dual channel memory so four of a typical X299 motherboardís eight DIMM slots will become non-functional. They also have just on-chip 16 PCIe lanes so connectivity options are further limited beyond even the diminished i7-78xx series. Turbo Boost Max 3.0 isnít available either and the new baseline architectural improvements of Skylake-X like its mesh interconnect and updated caching hierarchy have been consigned to the dustbin as well.

If all of these cuts make Kaby Lake-X sound strangely familiar, thatís because they should. You see, these new processors are carried over lock, stock and barrel from their LGA1151 stablemates. Think of them as standard Kaby Lake processors simply soldered onto an LGA2066 die and then given a slight bump in official memory support to 2666MHz.

Sitting atop of this particular lineup is the i7-7740X which, like the 7700K has four logical cores which account for eight processing threads. The base clock has received an insignificant bump of 100MHz to 4.3GHz in an effort to slightly differentiate this processor from one that has been on the market for the better part of six months now. At $339 even its cost aligns perfectly with the LGA1151-bound alternative.

The i7-7640Xís story is pretty much the same as its sibling. Thereís a very minor 200MHz improvement in the Base Clock but nothing has been touched within the Turbo rates. Pricing aligns with the i7-7600K as well so there really isnít anything here to differentiate the two other than the platform upon which they are used.

TDP will be an interesting factor with the Kaby Lake-X processors since theyíre rated for 112W versus the frugal 91W of Kaby Lake-S. Naturally there will be some efficiency losses when moving to such a large die package but donít take this to mean theyíre going to consume significantly more power. Rather, the additional TDP headroom could conceivably given these two CPUs the ability to maintain higher speeds more frequently and also offer more overclocking. Maybe.

At this point you are probably wondering why these processors are even a thing. I actually donít have any direct answer to that but Intelís official line is that they give additional choices to buyers who may want to buy into the 2066 platform and do so at a reduced cost. That explanation provides few insights into the situation given the fact that installing a Kaby Lake-X processor onto an X299 motherboard wonít net you any additional features over Z270.

The addition of Kaby Lake-X has also necessitated the aforementioned nerfing of i7-7800-series chips since Intel sort of backed themselves into a corner. You see, if they carried over the 6800-series PCIe lane allocation but maintained a pricing structure that competed against AMDís Ryzen CPUs (make no mistake about it, the 7800Xís $389 price point is still quite tempting), sales of Kaby Lake-S processors like the 7700K could have been compromised.

Now with Kaby Lake-X processors the lines of distinction between product lineups are further blurred and thereís something of a logjam between the $299 and $399 brackets. Their addition has also forced Intelís hand to make a CPU like the i7-7820X which features 28 PCIe lanes lest it becomes overly popular from a price / performance standpoint.

It is hard to predict where we go from here too. Any faster Kaby Lake CPUs or upcoming 14nm refreshes will invariably compete with some pretty major elements in Intelís HEDT lineup, particularly now that Kaby Lake-X is a thing. Meanwhile, Intel has obviously left some space open for future expansion. It could very well be that any higher end additions to the Kaby Lake lineup will be made on the 2066 socket rather than 1151. That may go for the upcoming Cannon Lake and Coffee Lake as well. Only time will tell.

With all of this being said, I do think thereís a silver lining on Kaby Lake-X. Whereas the 7700K and 7600K represent the very pinnacle of Intelís 1151 platform, the i7-7740X and i7-7640X could conceivably act as a great gateway into a platform thatís rife with upgrade possibilities down the road. X299 will stick around for a while folks. That means you can buy a sub-$400 processor and X299 board now and then simply drop in a higher end CPU sometime down the road rather than requiring a massive system upgrade. Itís a tantalizing possibility for people who want to hedge their bets against future requirements in their workflow.

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