Windows 10 VM Now Suddenly Slow


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Hey everybody!

 

I've been running a Windows 10 VM on my Unraid server for a year or so and haven't had any problems.  Earlier today I upgraded Unraid server to 6.9.1 (it was on 6.9.0 rc, so was overdue).  Now that I've done that, I've noticed my VM is running extremely slow.  I'm not sure what could have changed, unless there was something in the upgrade that is adversely affecting it.  I run the VM on a dedicated SSD which is no where near full.  I've made no changes to the VM since the upgrade (like adjusting the CPU/RAM/etc); everything is exactly as it was.  When I'm using Remote Desktop and connect, everything seems so slow and sluggish.  I'll click on something, and there is a definite 3-5 second pause before I see the reaction.  If I open the task manager, I do see a rather large chunk of memory (25-30%) being used with a programmed called "Antimalware Service Executable" although I don't understand why that would cause things to be crawling.  Something else I've noticed a lot of is the connection just seems to drop.  I'll be clicking on things and nothing at all happens, close and reopen the connection and everything was doing as expected but it never sent the information across the connection.   As for my Remote Desktop connection, everything is wired, and I'm local (sitting less than 3 feet from server), and nothing has changed since it was working before.  For troubleshooting, I have shutdown and restarted the VM 3 times, and I've also gone in and did a reboot and then also a shutdown/wait/reboot of the Unraid just to be sure. 

 

Would really appreciate it if anybody out there has experience with this and could help me.

 

Thanks!

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I might be experiencing the same symptoms.  I upgraded from 6.8.3 to 6.9.0 and now to 6.9.1 and my Win10 VMs seem to be running much slower.  I see long periods of high CPU utilization on a fresh boot with no applications started.  Out of curiosity, do you store your VM disk images on an SSD cache pool?  I just moved all of VM disk images off the cache and onto the array, and so far, it seems to help.  Going to do some more testing, but I was planning to move everything off cache and repartition the SSDs to 1MB alignment anyways.  Once aligned, I'll move the VM disk images back to cache to see if it helps.

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From what I've researched, having your VM on the array is actually slower.  Putting it on the cache and setting it as "Cache Only" is the usual best suggestion I've seen.  However, in my case I have it on it's own SSD (which is an NVME, not a 2.5-inch), and have that mapped through Unassigned Devices.  I thought maybe the system had detected something like new hardware or something since the problem appeared right after updating Unraid.  Like maybe the drivers for the VM are different so Windows was choking somewhere.  Strangely enough, I let it run overnight and the next day it was back to running as fast as it should have been.  So maybe my thoughts were somewhat accurate and Windows was processing some driver update.  I'm definitely going to continue monitoring it, because it was extremely odd.

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I’m a newbie so didn’t have a previously-performant Windows 10 VM, but for me I tried to set mine up first with a GPU vBIOS grabbed from the online database—which didn’t work at all—and then pulled off of my GTX 1080 with the vBIOS tool. The latter worked but was noticeably _slower_ than not passing in a vBIOS at all.

 

Insofar as the changes to the VM manager I’ve read in the changelog since 6.8, one thing I might check is ensuring you have a) CPU isolation and b) no “odd hyperthreads”—cases where you’ve assigned one hyperthread of a core and not the other(s).

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Experiencing something similar.  I use a Windows VM (in cache) to run video conversions from time to time.  I normally get about 50+ fps when encoding.  After 6.9.1, it tops out at around 10fps and all cores show max loads.  I use the Handbrake docker as well and there is no drop in performance there.

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Do we have any new information about this? My CPU utilization is constantly 100%. I'm using a passthrough and I can't seem to modify this. This only happened with the upgrade so I'm 100% certain it's upgrade related. Is there anything I can try? I need to use these VMs and right now they're 100% useless.

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I spent the weekend trying to diagnose the problems and I may have found something.  These are the things I've tried with mixed results:

 

  • Moved everything off my cache pool (2 Samsung EVO SSDs), repartitioned to 1MB alignment, moved everything back (my vdisks are on the cache pool)
  • Updated virtio windows drivers to latest (0.1.190-1)
  • Updated VM Machine to i440fx-5.1 (was i440fx-4.2)
  • Changed VM network model to virtio-net (was virtio)
  • Reduced RAM to 16384 MB (was 32768 MB)
  • Moved Windows 10 VM vdisk to separate SSD in unassigned devices
  • Changed VM to use /dev/urandom for RNG

I have two Windows 10 VMs and only one is having problems.  The last change I made this morning looks to have resolved the issue for me.  In the Windows 10 VM that is slow, I went into Windows Features and disabled Hyper-V, Windows Hypervisor Platform and Windows Subsystem for Linux.  After the required reboot, I no longer saw all cores hitting 100% with 50-80% from system processes.  I also saw a dramatic change in the interrupt processing on the cores dedicated to that VM from Unraid's perspective.  My next step is to turn Windows Subsystem for Linux back on since I do need it for this VM.

 

Hope this info helps some of you experiencing slowness.

Edited by ncandy
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16 hours ago, severanced said:

OK, I fixed it, I was using the passthrough mode for the CPU and I switched it to the emulated version using this and it seems to have fixed the issue for me.

I spoke too soon, I got in, reinstalled some drivers, rebooted and now the VM won't start properly, nothing I do helps so I just have to rebuild it. :(

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20 hours ago, severanced said:

OK, I fixed it, I was using the passthrough mode for the CPU and I switched it to the emulated version using this and it seems to have fixed the issue for me.

Could you elaborate on what “this” is? Your link is to the release notes for 6.9.0-beta25 and it’s not clear what “the emulated version” refers to in that context. What did you change, settings-wise?

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3 hours ago, TreyH said:

Could you elaborate on what “this” is? Your link is to the release notes for 6.9.0-beta25 and it’s not clear what “the emulated version” refers to in that context. What did you change, settings-wise?

It was in reference to changing the XML file to remove the passthrough notation, but it doesn't matter as it ended up corrupting my VM and now I have to rebuild it anyway, oh well.

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So it seems that nested virtualization was causing problems in my case.  I reenabled WSL but left off Hyper-V and Windows Hypervisor Platform and everything is running normally.  Interestingly, turning off Hyper-V in the Unraid VM settings did nothing to resolve the issue.  I needed to disable virtualization features inside Windows itself.

 

 

Screenshot 2021-03-18 072906.png

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  • 4 weeks later...
  • 2 weeks later...

same problem here with 6.9.1, my windows 10 VM is unusable....really slow, really anoying

 

 

semm to be solved with unraid tips trick =>  CPU Scaling Governor was on save, put it  "on demand"

Edited by ibasaw
  • Thanks 1
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  • 3 weeks later...
On 3/18/2021 at 12:38 PM, ncandy said:

So it seems that nested virtualization was causing problems in my case.  I reenabled WSL but left off Hyper-V and Windows Hypervisor Platform and everything is running normally.  Interestingly, turning off Hyper-V in the Unraid VM settings did nothing to resolve the issue.  I needed to disable virtualization features inside Windows itself.

 

 

 

Yes Sir, this solved my bad VM-performence aswell. But i had the problem with deactivate the hyper-v. If this happen, use this command in prompt as Administrator. bcdedit /set hypervisorlaunchtype off 

  • Like 1
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  • 3 weeks later...
On 5/12/2021 at 11:32 PM, Ghostly2002 said:

Yes Sir, this solved my bad VM-performence aswell. But i had the problem with deactivate the hyper-v. If this happen, use this command in prompt as Administrator. bcdedit /set hypervisorlaunchtype off 

 

I have also bad performance problems but these occurs just when I access shares on the unraid and move files from unraid to unraid and so on. Then my Win 10 VM gets unusable slow till the transfers are finished.

My VM got 12 Cores, 16GB RAM, Passedthrough SSD (its own SSD not a VDISK), Passedthrough RX580.

My problems just are noticable when accessing files on unraid, like opening a archiv file, moving or copying files within unraid or from my VM to a unraid share... Even while downloading directly with Firefox within my VM it gets slow asf... (Sorry but its laggy and unsuable till downloads/file accessing/moving/copying is finished).

With my MacOS VM also 12 Cores, 16GB RAM, Passedthrough SSD (its own SSD not a VDISK), Passedthrough RX580... Everyhing there works "normally"...

When I use my gaming PC to access unraid and move or copy files everything is fine and useable even on the VM, also my problem just occurs when use my Win 10 VM and I do something on the unraid shares and or do some downloads within my VM....

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On 4/24/2021 at 10:55 AM, ibasaw said:

same problem here with 6.9.1, my windows 10 VM is unusable....really slow, really anoying

 

 

semm to be solved with unraid tips trick =>  CPU Scaling Governor was on save, put it  "on demand"

 

I did exactly this, in tips and tweaks modified the CPU scaling governor from "power saving" to "on demand" and its resolved the issue.   

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  • 2 weeks later...
  • 2 weeks later...

hi i having similar problems

i tried the cpu scalling on demand and the set 1440fx-3.1   i didnt have Hyper-V insstalled so i didnt need to disable it

 

but im using DJ software  Virtual DJ  and a mixer i have... and it cuts out the audio   choppy..  all 6 cores run 100%  idling  runs at 80-100 percent..

if i run  Windows Media Player to play an MP3 it stays around below 50%  or so  but it doesnt seem to stutter playback through a mixer using the usb port

but when i run the App it does.,,,  running on a bare metal or a laptop  it doesnt use that muci cpu usage... are there any other tricks why shes sooooooooo slow, choppy, and constantly running 100% on all cores

 

 

it runs 80% just being loading up doing nothing

 

vm1a.PNG

Edited by comet424
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  • 1 month later...

I had the same problem, switching the machine to i440fx-3.1 and disabling virtualization in the VM settings. After I did this my CPU dropped from 99% all the time to 30%. 

 

Not sure if this will fix the issue for everyone but it sure did for me.

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  • 2 weeks later...
On 6/8/2021 at 4:11 AM, joedotmac said:

 

I did exactly this, in tips and tweaks modified the CPU scaling governor from "power saving" to "on demand" and its resolved the issue.   

I too fixed my performance issues by changing the value to 'On Demand' I wonder if this should be the default if it gives much better performance

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