6.9.0-beta25 - VM Showing wrong CPU?

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You did some custom edits in the xml for the CPU. Not sure if you found it on the unraid forum or somewhere else. Usual it's used to get better performance and compatibility with Ryzen CPUs. This long list of defined feature sets I never used myself before, only a couple of them. As long as it works for you and the performance is ok, I see no issue here.


  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>EPYC-IBPB</model>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='tsc-deadline'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='tsc_adjust'/>
    <feature policy='require' name='clwb'/>
    <feature policy='require' name='umip'/>
    <feature policy='require' name='stibp'/>
    <feature policy='require' name='arch-capabilities'/>
    <feature policy='require' name='ssbd'/>
    <feature policy='require' name='xsaves'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='clzero'/>
    <feature policy='require' name='wbnoinvd'/>
    <feature policy='require' name='amd-ssbd'/>
    <feature policy='require' name='virt-ssbd'/>
    <feature policy='require' name='rdctl-no'/>
    <feature policy='require' name='skip-l1dfl-vmentry'/>
    <feature policy='require' name='mds-no'/>
    <feature policy='require' name='pschange-mc-no'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='require' name='topoext'/>
    <feature policy='disable' name='svm'/>


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Nope, didn't do those myself. I've only added the multifunction for GPU passthrough. Perhaps they appeared when I set it to Emulated for the CPU Mode instead of Passthrough? I had to do that due to the BSOD Kernel Security Check issue when Windows would boot.


I'm looking because I am having performance issues (specifically on the one game I'm setting this up to play - Final Fantasy XV Windows Edition). When I play the CPU is maxed out and the game gets like 10 FPS sometimes even on Medium settings and 1080P, even though my GPU and specs are above what is required for 4k.

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@duffbeer Trust me the "EPYC tweak" is a custom edit done by the user and not from a setting made by Unraid. Usually only the following is needed and is reported in a couple tutorials here in the forums. In Unraid you only can set it to emulate a QEMU64 CPU not an EPYC or Skylake or whatever.

  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>EPYC</model>
    <topology sockets='1' cores='7' threads='2'/>
    <cache level='3' mode='emulate'/>
    <feature policy='require' name='topoext'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='svm'/>
    <feature policy='disable' name='x2apic'/>

Forcing the VM to use some specific CPU features can end up emulating features wich aren't present in the physical CPU. In general this tweaks are needed for first and 2nd gen Ryzen chips and Threadrippers. Maybe try to remove them and test without. The only one which by default Unraid sets is the following.

  <cpu mode='host-passthrough' check='none'>
    <topology sockets='1' cores='3' threads='2'/>
    <cache mode='passthrough'/>
    <feature policy='require' name='topoext'/>

Try it with the snippet above and adjust the core/thread counts so it matches your needs.

Edited by bastl
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I went to look at my XML while my VM was powered off, and those settings weren't there.

When I powered on the VM then went to edit the same XML again, all of that appeared.

Does that change anything? Should I manually set those parameters BEFORE the VM is powered on so they override what (I assume is unRAID) is trying to do?
I've attached the "powered off XML" now so it can be compared.


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I can confirm this behaviour, powered off I have "host-model" for CPU (own edit to get win 10 to work with ryzen 3), but if I look at the xml with the machine powered on I can see the same "features" as the OP, but this is all reverted back when machine is powered off again.

And indows reports it as "EPYC", same as OP.

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  • 5 weeks later...

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