Enabling vt-d or vt-x and not using it?

Discussion in 'Virtualized Computing' started by Valnar, Mar 4, 2018.

  1. Valnar

    Valnar [H]ardness Supreme

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    OK so this is sort of an anti-VM question and I really should know the answer to this, but don't...

    I have a PC where I'd like to squeeze the most performance out of it possible, and normally I enable vt-d and vt-x in the BIOS whether I'm running VMware Workstation, VirtualBox or not. I leave it on in case I need it on most of my builds.

    In this case, this particular PC will not run any virtuals. Is there any detriment to leaving that feature on and not using it? Or is there an advantage to turning them off if you aren't using them?
     
  2. SolarBeam

    SolarBeam n00bie

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    If you don't need it, disabling it via the BIOS is fine.
    In terms of stability, having it enabled or disabled shouldn't hinder/benefit the stability/performance of a PC. If you're not using software that is making use of virtualization, it should not affect performance.
    I've had virtualization both enabled and disabled and when I've run benchmarks and stress testing applications, I've never seen a performance drop or a stability issue.
     
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  3. Sycraft

    Sycraft [H]ardness Supreme

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    There are two minor considerations that I'm aware of related to VT-x:

    1) It is required from Windows new credential guard system that hides password hashes away from utilities like mimikatz. Now the utility of that on a home system is a little questionable since if someone gets in to your system, they've owned you, there's no need to try and pass the hash to other systems to escalate to admin account. Not something I'd worry about, but something to know.

    2) With VT-x on I've observed slightly higher interrupt to process latency. I haven't done enough testing to say this for 100% certain in all situations, but it seems to be that you increase your latency a bit. Again, that isn't something to worry about on a normal home system, really matters only if you are doing ultra low latency pro audio or the like.