Intel Core i7-7740X Kaby Lake-X Review

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Temperature Curves & Delta Values

Cooling Nuclear Option: The Chiller

Again, we used our Alphacool Eiszeit Chiller 2000 to produce results that are comparable to those from our Core i9-7900X review. We also used this cooler in all of our AMD Ryzen reviews, which means that those results can be compared as well.

High Temperature Differences Challenge Cooling Performance

Kaby Lake-X suffers from Intel's use of thermal paste between the die and heat spreader. Solder would have been the way to go. The difference between the water block’s temperature, which is held at a constant 20°C, and the CPU temperature (according to its sensors) demonstrate this point nicely.

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.

The next graph represents the temperature difference between the top of the CPU's heat spreader and cores.

Our cooling solution is one of the best you can buy. Nevertheless, we measure a 48°C difference between the top of the Core i7-7740X's heat spreader and its cores. This isn't a horrible result, but it could have been a lot better.

Leakage

Next, we measured power consumption at an identical load using different cooling solutions. The leakage currents were below our measurement equipment’s accuracy range. For this reason, we didn't bother with a graph. Kaby Lake-X doesn't have a problem with leakage currents that could increase power consumption in a meaningful way.

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Intel Core i7-7740X Kaby Lake-X
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Previous Next
Summary
  1. Kaby Lake Paddles Into HEDT
  2. Test Setup
  3. VRMark, 3DMark & AotS: Escalation
  4. Civilization VI & Battlefield 1
  5. GTA V, Hitman & Shadow of Mordor
  6. Project CARS & Rise of the Tomb Raider
  7. Workstation & HPC Performance
  8. Power Consumption & Overclocking
  9. Temperature Curves & Delta Values
  10. Final Analysis
About the author
Paul Alcorn & Igor Wallossek

Paul Alcorn is a Senior Editor for Tom's Hardware US. He writes news and reviews on CPUs, storage and enterprise hardware.

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  • 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
    Quote:
    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).
  • keith12
    in the HPC graph, you have two 'Ryzen 7 1600x' s.....
  • keith12
    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.
  • AgentLozen
    Quote:
    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.


    I agree that it's cool you have upgrade options when you buy an x299 motherboard. You can spend $350 on Kaby Lake X now then drop another $1000 in the future if you feel the need to buy Skylake X. It seems like Tomshardware didn't give credit to this upgrade path $1350 upgrade path where it's due.

    Some people might just buy Skylake X to begin with and save $350 on Kaby Lake X, but I ask "Why not both?"

    I think you hit the nail on the head on your x299 chipset point. The x270 chipset was obsolete when it launched with Kaby Lake 6 months ago. I'm glad Intel is giving a chance to rectify the situation by giving us access to the x299 chipset. So what if most of the motherboard is disabled because of the architectural differences between Kaby Lake X and Skylake X? What were you going to use those extra PCIe lanes for? Extra professional devices? Psh, whatever.

    Good point about the heat too. I'm tired of people using lines and graphs for stuff. It makes my head hurt. These nerds at Tomshardware could learn a thing or two from our president and just ignore that crap. The heat won't be a problem until you start Windows. That's why you use LINUX!

    Thanks for posting freak777power. We friends <3
  • mossberg
    2164959 said:
    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.


    I would rather take that $60 and get a better graphics card. Why waste this kind of money on a 4c/8t system, when you can get a Ryzen 1700, with 8c/16t, for a similar cost? The R7's are plenty capable at gaming, and are great in workstation type apps. X299 is an overpriced waste of time. I think Linus had it right when he called it a knee jerk reaction.
  • PaulAlcorn
    1636679 said:
    Quote:
    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).


    We've done a LOT of Ryzen reviews, so this might not be the only one that included the test data.

    http://www.tomshardware.com/reviews/amd-ryzen-5-1600x-cpu-review,5014-8.html

    I'll circle back with Igor about the axis.
  • PaulAlcorn
    182540 said:
    in the HPC graph, you have two 'Ryzen 7 1600x' s.....


    Which particular graph? I'm looking over them, but don't see it.
  • PaulAlcorn
    182540 said:
    in the HPC graph, you have two 'Ryzen 7 1600x' s.....


    Which particular graph? I'm looking over them, but don't see it.
  • PaulAlcorn
    2164959 said:
    And as for heat...i think heat talk i have been reading lately is just BS.


    http://www.tomshardware.com/reviews/-intel-skylake-x-overclocking-thermal-issues,5117.html
  • I setup couple machines with x299 with 6 and 8 cores for other people and with 4.2Ghz on 8 Core and 4.5Ghz on 6 Core overclock nowhere to see heat problem. Granted we didn't run Prime but guess what, who plays Prime95 anyway? That unrealistic test will heat up anything you throw at. In other words in everything else i haven't seen 8 core going over 60C at all and idles between 25/30C and entire setup was in Thermaltake X31 with one of the AIO 240mm watercooling kits. I still say, this heat talk is just BS.
  • 496490 said:
    Quote:
    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.
    I agree that it's cool you have upgrade options when you buy an x299 motherboard. You can spend $350 on Kaby Lake X now then drop another $1000 in the future if you feel the need to buy Skylake X. It seems like Tomshardware didn't give credit to this upgrade path $1350 upgrade path where it's due. Some people might just buy Skylake X to begin with and save $350 on Kaby Lake X, but I ask "Why not both?" I think you hit the nail on the head on your x299 chipset point. The x270 chipset was obsolete when it launched with Kaby Lake 6 months ago. I'm glad Intel is giving a chance to rectify the situation by giving us access to the x299 chipset. So what if most of the motherboard is disabled because of the architectural differences between Kaby Lake X and Skylake X? What were you going to use those extra PCIe lanes for? Extra professional devices? Psh, whatever. Good point about the heat too. I'm tired of people using lines and graphs for stuff. It makes my head hurt. These nerds at Tomshardware could learn a thing or two from our president and just ignore that crap. The heat won't be a problem until you start Windows. That's why you use LINUX! Thanks for posting freak777power. We friends <3


    I find your post rather pretty amusing. Extra PCIe lanes get disabled but that's because of number of PCIe quad core carries, nothing there to worry about. Again $219 x299 is way better deal than Z270 giving you hell of more options currently and in the future. I setup couple 6 and 8 core x299 machines and haven't seen any heat or throttling issues. Rule of thumb is don't trust anything you read these days and do your own research and then make conclusion.
  • TJ Hooker
    1920539 said:
    1636679 said:
    Quote:
    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).
    We've done a LOT of Ryzen reviews, so this might not be the only one that included the test data. http://www.tomshardware.com/reviews/amd-ryzen-5-1600x-cpu-review,5014-8.html I'll circle back with Igor about the axis.

    Thanks. If we get the horizontal axis for the graph, we could then look at the slopes of the core temp vs power for Ryzen/Skylake-X/Kaby Lake-X (all using a constant 20C waterblock) as a way to compare the effective thermal resistance of their respective TIM+heatspreader.
  • tuvok
    Good review, now de-lid it and pair with 3600Mhz+ ram and stretch its legs.
  • the nerd 389
    127027 said:
    Good review, now de-lid it and pair with 3600Mhz+ ram and stretch its legs.


    It doesn't make much sense to de-lid the 7740x. It's main advantage is that you can upgrade to Skylake-X without replacing the motherboard. You don't de-lid a CPU if you can't afford the next better CPU (assuming you're not making a more fundamental mistake). Beyond that, the 7740x has marginally higher clock speeds, but that is a moot point if you compare a de-lidded 7740x to a de-lidded 7700k.

    Add the price difference into the mix, and things quickly favor the 7700k. Not including the platform, you'll probably screw up your first one or two attempts at replacing the TIM. That means the 7700k has an advantage of $100-$150 in the CPU alone. Once you account for that motherboard, you're down several hundred dollars if you go with the 7740x.

    For the additional money, you don't really get anything. The additional capabilities of the x299 are totally lost on the 7740x.
  • jimmysmitty
    496490 said:
    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?


    Probably Coffee Lake and/or Cannon Lake X since those are the next upcoming uArchs.
  • abbadon_34
    What happen to -X actually being "High End Desktop" ? This is 4 cores, dual channel, restricted PCI-E lanes, nothing like the previous -X series. Only thing is it requires an expensive motherboard. WTF???
  • the nerd 389
    182243 said:
    What happen to -X actually being "High End Desktop" ? This is 4 cores, dual channel, restricted PCI-E lanes, nothing like the previous -X series. Only thing is it requires an expensive motherboard. WTF???


    You've nicely summarized the general opinion of the i7-7740x and the i5-7640x.
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