Intel Core i7-7740X Kaby Lake-X Review

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Civilization VI & Battlefield 1

Civilization VI AI Test

Clock rate and IPC throughput tend to win the day in this test, so it isn't surprising to find both Core i7s vying for supremacy.

It was less expected to find the 10-core Core i9-7900X mixing it up. Surely, a tuned Core i7-7700K would be faster at 4.9 GHz, right? The new Skylake-X model likely benefits from to its reworked cache hierarchy.

Again, the differences are slight between Kaby Lake-X and Kaby Lake-S. They're such similar processors, after all.

Civilization VI Graphics Test

Speaking of the -7900X's reworked cache hierarchy, as we noticed in our initial review, the processor does suffer from mesh-imposed performance limitations in some titles. That comes into play during this benchmark.

The 10-core Broadwell-E-based chip leads, but both tuned Core i7s are competitive with the rest of our contenders. The difference between Core i7-7700K and -7440X is negligible at stock settings, and therefore unnoticeable during gameplay. But the -7740X's extra bit of frequency headroom yields a larger delta when we overclock.

Battlefield 1 (DX11)

Our armor-laden walk through the O La Vittoria scene in Battlefield 1 yields large performance variations when we test less-powerful processors. The differences shrink as we benchmark higher-end CPUs, mostly because we're graphics-bound.

We encountered an almost-predictable variance between the two Core i7s in most tests, and that plays out in Battlefield 1 when we measure the stock configurations. A 0.2 FPS delta is simply imperceptible.

The story changes with the application of a robust overclock, though. Try as we might, we simply could not get Intel's -7740X to match the -7700K in an overclocked state. That's particularly baffling due Kaby Lake-X's higher overclocked frequency. Nevertheless, the results for both overclocked Core i7s are repeatable, so it's possible that BIOS updates or chipset drivers could improve performance down the road.


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Paul Alcorn
Managing Editor: News and Emerging Tech

Paul Alcorn is the Managing Editor: News and Emerging Tech for Tom's Hardware US. He also writes news and reviews on CPUs, storage, and enterprise hardware.

  • AgentLozen
    I'm glad that the option for Kaby Lake is available on the x299 chipset. In practice it seems impractical. This article shows you have to pay a lot more for slightly higher overclocking potential.

    I'm curious what Intel's plans are for next year regarding their high end desktop chips. They've already used the Kaby Lake X name for this generation. Should we expect Kaby Lake X 8900X?
  • Kaz_2_
    Intel high power consumption is not great in thr long run. You want the best for your investment
  • TJ Hooker
    The curve below shows clearly that waste heat isn't dissipated quickly enough. Just as we did in our AMD Ryzen and Intel Core i9 launch articles, we used a very thin copper plate to measure the heat spreader's temperatures as well.
    Why aren't there any numbers/divisions on the horizontal axis? Also, you say you did the same thing for the Ryzen reviews but I didn't see a similar graph in those articles (might just be blind though).
  • Roland Of Gilead
    in the HPC graph, you have two 'Ryzen 7 1600x' s.....
  • Roland Of Gilead
    power consumption gaming loop - I5 7600x?
  • the nerd 389
    How does the thermal performance of this chip compare to the 7700k? Specifically, does the larger surface area of the heat spreader give you a meaningful increase in thermal conductivity between the die and the heatsink?
  • rantoc
    Dang intel seem to be doing yet another stupid move with X299 beside rushing it out the door making the AMD's pretty brand new architecture/platform appear mature in comparison. As for this move - What's the incentive to pay premium for the X299 when getting a chip like this that won't even utilize it fully? The 7700k and platform are equal in performance in most tests and far cheaper...

    With the poor thermal transfer between the core and heat-spreader the retail chips won't likely even overclock well either. Never cared about the cherry picked "reviews" chips at all when it comes to overclocking as they very rarely represent the retail chips.
  • rantoc
    What's the incentive to buy an expensive motherboard and yet get near zero of it's true potential with this cpu? That's paying for a lot of real estate that can't be used at all and on top of that the same poor thermal transfer between the core and heat-spreader meaning a good stable oc is harder to obtain and far less likely to happen on the retail IE non-review cherry picked ones.

    I think intel shoot themselves in the foot by scaling this one down to much and then couple it with an overpriced platform for what you get out of it, x299 will be good no doubt but only with the right chips and only when the rushed out of door bugs been fixed.
  • This is awesome setup because you can buy x299 motherboard for $219 dollars already which gives you amazing room for later upgrade and this CPU can run 5.0Ghz easily producing very little heat. People at Toms Hardware completely missed the point. I'd rather get $219 x299 motherboard than outdated Z270 for $160.
  • And as for heat...i think heat talk i have been reading lately is just BS.