How to Stress-Test CPUs and PCs (Like We Do)

CPU Only: Measuring Power Consumption With Different Stress Tests

Regardless of whether you're talking about CPUs or graphics cards, the general principle remains the same: however much energy is put in reemerges as waste heat.

To that end, we start by observing the CPU's power consumption via its package. Differences between various architectures and models can be massive. But our Core i7-8700 does a fairly good job of representing the upper-mid-range, given its 65W TDP.

Prime95 with AVX and Small FFTs takes first place in our comparison of stress tests, followed by powerMAX with AVX and AIDA64’s FPU test.

The top three finishers land in their same positions, though the rest of the field shuffles around a bit. This is due to variances in certain loads, such as the memory tests. Moreover, there are slightly different voltage converter losses attributable to dissimilar load patterns.

We decided to present the deltas between overall power consumption and individual results as well, since some of them are pretty massive. This comparison allows for an estimate of how much additional waste heat is generated by the system that the CPU cooler can't take care of. Keep these numbers in mind if you're building a water-cooled system; proper ventilation is how you'll have to cope with the extra heat.

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  • WINTERLORD
    Is this like a fancy water cooler im guessing? what about a typical AIO cooler. In fact i have a skyth fuma but may save up to get some kind of AIO water cooling been tryin to find decent reviews on decent water coolers both cheap and if needed high end. not no alpha cooler though lol
    Alphacool Eisblock XPX ($73.99 On Newegg)
    Alphacool Eiszeit 2000 Chiller
  • FormatC
    This is a high-end compressor cooler for up to 1500 watts heat input. It's a modified version from industry and mostly used to cool the head of powerful laser cutters. Why I'm using this one? To show, which program is able to do it right. If you have additionally limitations from coolers, thermal throttling and other funny things, you will never see the exact difference. I can keep a constant water temperature of 20°C to make all the test results comparable. ;)
  • Th_Redman
    What did you guys put on the hotdog after testing? A little mustard, ketchup, relish, sauerkraut...? LOL.
  • WINTERLORD
    is actually a great article one can resort reference too. Good Job!
  • aquielisunari
    I use Aida, Prime 26.6, Superposition, UserBenchmark, MSI's kombustor and I no longer use Heaven. I may be forgetting a couple. But something has always felt a little off. I finally see what it was. My build was missing a hotdog and its bun. I always do love learning from the pros. I placed it on a piece of parchment and instantly I notice a difference.

    I routinely check temperatures, loads and other info from my system. I also stress test with different CPU and GPU benchmark/stress test software. Thanks for the info. Page bookmarked.
  • CompuTronix
    As the author of the Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html - I can fully appreciate how much work went into creating this outstanding article, which has been sorely needed!

    Since most users test their rigs without a sense of scale for power and temperature, they can't compare apples to apples, especially when combined with major variables such as differences in ambient temperature, hardware configurations and software utilities. This article provides a perspective and some excellent comparisons.

    The Intel Temperature Guide differs in its approach toward the topic of processor Core temperatures and cooling with respect to Intel's TDP specifications, and distinguishes between steady workloads for thermal testing versus fluctuating workloads for stability testing. Nevertheless, our results are very similar.

    However, since Intel validates their thermal specifications at a steady 100% TDP, it's most appropriate to select utilities that don't overload or underload the CPU. The only utilities I've ever found that come as close as possible to 100% TDP are Prime95 v26.6 Small FFT's as a steady workload for thermal testing, and Asus RealBench as a fluctuating workload for stability testing.

    Although the topic of Prime95 (with and without AVX) was covered, I would like to have seen RealBench included in your test suite,since it's widely accepted as an excellent utility for testing overall system stability, and uses a realistic AVX workload.

    Otherwise, great work! I was very pleased to read this article!

    CT :sol:
  • cangelini
    111321 said:
    As the author of the Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html - I can fully appreciate how much work went into creating this outstanding article, which has been sorely needed! Since most users test their rigs without a sense of scale for power and temperature, they can't compare apples to apples, especially when combined with major variables such as differences in ambient temperature, hardware configurations and software utilities. This article provides some excellent comparisons. The Intel Temperature Guide differs in its approach toward the topic of processor Core temperatures and cooling with respect to Intel's TDP specifications, and distinguishes between steady workloads for thermal testing versus fluctuating workloads for stability testing. Nevertheless, our results are very similar. However, since Intel validates their thermal specifications at a steady 100% TDP, it's most appropriate to select utilities that don't overload or underload the CPU. The only utilities I've ever found that come as close as possible to 100% TDP are Prime95 v26.6 Small FFT's for thermal testing, which is a steady workload, and Asus RealBench for stability testing, which is a fluctuating workload. Although the topic of Prime95 (with and without AVX) was covered, I would like to have seen RealBench included in your test suite, as it's widely accepted as an excellent utility for testing overall system stability, and uses a realistic AVX workload. Otherwise, great work! I was very pleased to read this article! CT :sol:


    That's an awesome resource, CT!
  • WyomingKnott
    442003 said:
    What did you guys put on the hotdog after testing? A little mustard, ketchup, relish, sauerkraut...? LOL.


    Thermal compound. Why not? People have used condiments between their CPUs and their coolers.
  • FormatC
    Step 1 - Collect all what I need:


    Step 2 - Start the oven


    Step 3 - Enjoy!

    The benchmark:



    The complete review was so funny, but it was never translated :(