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Do The Meltdown and Spectre Patches Affect PC Gaming Performance? 10 CPUs Tested

Game On...For Now

This first round of Meltdown and Spectre patch testing proved fairly uneventful. There really wasn't much to report across our suite of game benchmarks. But that's partly because the status of patches keeps changing. We originally planned to test with both the operating system and microcode updates for Spectre Variant 2, which are expected to impose a significant performance overhead.

Unfortunately, Intel and its partners pulled the microcode patch during our testing, and AMD still doesn't have a fix of its own. We've been told that Intel's updated update is undergoing rigorous validation, but we don't have a time frame for its release. The same goes for AMD's Variant 2 microcode. Of course, we'll add test results with the new patches once they are available. 

For newer processors, it looks like the operating system patch won't affect gaming workloads much, if at all. Most games are confined to the user space and don't make frequent kernel calls, so it's possible that the impact on older CPUs could be minor as well (game testing on those is in-progress).

The current patch does have an impact on storage performance, at least when it's measured with synthetic benchmarks. A laggy hard drive would obviously affect level loading times and the storage subsystem's ability to feed the game engine, possibly resulting in choppy scene transitions. We scrutinized our load times and cut scenes closely, and while entry-level CPUs did take longer and were less smooth, it's hard to chalk that up to a security patch because slower processors are, well, slower. We didn't notice any dramatic changes in performance consistency or frame time variance, so any minor impact would likely be limited to storage-imposed symptoms, at least with the patches as they sit currently.

Most of the vulnerability-oriented storage testing we've seen is happening at high queue depths, or using pure read or write workloads that aren't the best indicator of operating system performance. Most real-world accesses occur at lower queue depths, and radical changes in SSD performance, either for better or worse, don't correspond linearly to application performance

The Spectre Variant 2 patches still loom large for Intel and AMD. Hopefully, both companies can deliver solid updates with minimal impact. We've heard that some applications can be optimized to minimize overhead. And Intel has mentioned that existing patches will mature into more efficient implementations.

For now we remain vulnerable to Spectre Variant 2, and proof-of-concept code is already popping up in the wild, unfortunately. That leaves us exposed while we wait on Intel and AMD, not to mention the rest of the industry, to correctly patch what could be the greatest vulnerability of our time. At least we can enjoy some gaming while we wait. 


MORE: CPU Security Flaw: All You Need To Know About Spectre


MORE: Best Gaming CPUs


MORE: Intel & AMD Processor Hierarchy

  • madvicker
    The majority of PC users are going to be on older CPUs than the ones you've tested. These results are only pertinent to the small % of people who have recently bought a CPU / new PC. What about the rest, the majority with older CPUs? That would be a much more useful and interesting analysis for most readers....
    Reply
  • nikolajj
    I would like to see this done with Intel gen 4 (maybe 3) and up.
    Reply
  • arielmansur
    Newer cpus don't get a performance penalty.. but older ones sure do get a noticeable one..
    Reply
  • salgado18
    20680472 said:
    The majority of PC users are going to be on older CPUs than the ones you've tested. These results are only pertinent to the small % of people who have recently bought a CPU / new PC. What about the rest, the majority with older CPUs? That would be a much more useful and interesting analysis for most readers....

    Last page, third paragraph:

    "so it's possible that the impact on older CPUs could be minor as well (game testing on those is in-progress)."
    Reply
  • ddearborn007
    Hmmm

    3/4 of all personal computers in the world today are NOT running windows 10. I don't know the exact percentage of gaming systems that are NOT running windows 10, but surely it is substantial.

    Why wasn't the performance hit measured on the operating system running 3/4 of all PC's in the world today published immediately? To date, it appears that these numbers are being withheld from the public; the only reason has to be that the performance hit is absolutely massive in many cases.........Oh, and out of the total number of PC's used world wide, "gaming" PC's are a very small percentage, again begging the question of why tests are only being published for windows 10....
    Reply
  • LORD_ORION
    Need to test older CPUs... or is this article designed by Intel to stop people from returning recently purchased CPUs.
    Reply
  • RCaron
    Excellent article Paul!

    I have a question.
    I read originally that AMD Zen architecture had near-immunity to Spectre variant 2 because a CPU specific code (password if you will) (that changes with each CPU) was required in order to exploit the CPU. Which is why AMD was claiming that Zen was almost immune to Spectre variant 2. Is this not the case?

    AMD continues to insist that Spectre 2 is difficult to exploit due to CPU architecture. You left this out, and you continually lumped AMD with Intel with respect to Spectre 2 vulnerability.

    This is misleading to your readers, and portrays a bias towards Intel.

    https://www.amd.com/en/corporate/speculative-execution
    Reply
  • tripleX
    20680748 said:
    Hmmm

    3/4 of all personal computers in the world today are NOT running windows 10. I don't know the exact percentage of gaming systems that are NOT running windows 10, but surely it is substantial.

    Why wasn't the performance hit measured on the operating system running 3/4 of all PC's in the world today published immediately? To date, it appears that these numbers are being withheld from the public; the only reason has to be that the performance hit is absolutely massive in many cases.........Oh, and out of the total number of PC's used world wide, "gaming" PC's are a very small percentage, again begging the question of why tests are only being published for windows 10....

    Global OS penetration for Win 10 and Win 7 is effectively tied.

    Reply
  • PaulAlcorn
    20680892 said:
    Excellent article Paul!

    I have a question.
    I read originally that AMD Zen architecture had near-immunity to Spectre variant 2 because a CPU specific code (password if you will) (that changes with each CPU) was required in order to exploit the CPU. Which is why AMD was claiming that Zen was almost immune to Spectre variant 2. Is this not the case?

    AMD continues to insist that Spectre 2 is difficult to exploit due to CPU architecture. You left this out, and you continually lumped AMD with Intel with respect to Spectre 2 vulnerability.

    This is misleading to your readers, and portrays a bias towards Intel.

    https://www.amd.com/en/corporate/speculative-execution

    From the AMD page (which you linked)

    Google Project Zero (GPZ) Variant 1 (Bounds Check Bypass or Spectre) is applicable to AMD processors.

    And...

    GPZ Variant 2 (Branch Target Injection or Spectre) is applicable to AMD processors.
    While we believe that AMD’s processor architectures make it difficult to exploit Variant 2, we continue to work closely with the industry on this threat. We have defined additional steps through a combination of processor microcode updates and OS patches that we will make available to AMD customers and partners to further mitigate the threat.
    AMD will make optional microcode updates available to our customers and partners for Ryzen and EPYC processors starting this week. We expect to make updates available for our previous generation products over the coming weeks. These software updates will be provided by system providers and OS vendors; please check with your supplier for the latest information on the available option for your configuration and requirements.
    Linux vendors have begun to roll out OS patches for AMD systems, and we are working closely with Microsoft on the timing for distributing their patches. We are also engaging closely with the Linux community on development of “return trampoline” (Retpoline) software mitigations.

    AMD hasn't released the microcode updates yet, but to its credit, it's probably better to make sure it is validated fully before release.
    Reply
  • DXRick
    Do the OS patches (without the microcode patches) fix the two exploits? If so, why would we even want the Intel patches at all?
    Reply