Windows VM with GPU passthrough seems slow and laggy

Arm1nas

Member
Feb 12, 2022
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0
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Hello, I have a Windows VM on proxmox with RTX 3060 ti passed through to it, using moonlight/parsec it seems slow and the games FPS seem low even though looking at the stats the CPU/GPU/RAM doesn't seem to be that loaded.
Can someone look at my configs and tell me where I could improve with the VM config?

Proxmox host:
AMD Ryzen 5 1600
DDR4 3200MHz 64GB (2x 32GB)
Motherboard: Gigabyte B450 Gaming X (rev. 1.x)
SSD: NVMe 1TB
GPU: RTX 3060 ti (passed through to VM)
Proxmox 8.1.3


Windows VM config:
Code:
agent: 1
args: -cpu host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_spinlocks=0x1fff,hv_vapic,hv_time,hv_reset,hv_vpindex,hv_runtime,hv_relaxed,hv_vendor_id=intel,vmware-cpuid-freq=false,enforce=false,host-phys-bits=true,hypervisor=off -smbios type=0,version=UX305UA.201 -smbios type=1,manufacturer=ASUS,product=UX305UA,version=2021.1 -smbios type=2,manufacturer=Intel,version=2021.5,product='Intel i9-12900K' -smbios type=3,manufacturer=XBZJ -smbios type=17,manufacturer=KINGSTON,loc_pfx=DDR5,speed=4800,serial=114514,part=FF63 -smbios type=4,manufacturer=Intel,max-speed=4800,current-speed=4800
audio0: device=ich9-intel-hda,driver=none
balloon: 0
bios: ovmf
boot: order=sata0;net0
cores: 12
cpu: host,flags=+pcid
efidisk0: local:100/vm-100-disk-0.qcow2,efitype=4m,pre-enrolled-keys=1,size=528K
hookscript: local:snippets/taskset-hook.sh
hostpci0: 0000:07:00,pcie=1
machine: pc-q35-8.0
memory: 24581
meta: creation-qemu=8.0.2,ctime=1701592092
name: win11
net0: virtio=CA:09:F3:97:56:0B,bridge=vmbr0,firewall=1
numa: 1
ostype: win11
sata0: local:100/vm-100-disk-1.raw,cache=unsafe,size=400G,ssd=1
sata1: /dev/disk/by-id/ata-WDC_WD10EZEX-00BBHA0_WD-WCC6Y7FUZN3L,size=976762584K
scsihw: virtio-scsi-single
smbios1: uuid=ab9f878b-b5c2-4686-9035-40c434f9c0a5,manufacturer=QVNVUw==,product=VVgzMDVVQQ==,version=MjAyMS4x,serial=MTI0NjY3,sku=MTM0NDY4,family=Ng==,base64=1
sockets: 1
tpmstate0: local:100/vm-100-disk-2.raw,size=4M,version=v2.0
vga: none
vmgenid: d09148f5-0240-4751-a5d2-da0a481112d4

Proxmox GRUB config:
Code:
GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt pcie_acs_override=downstream,multifunction"
GRUB_CMDLINE_LINUX=""
 
You shouldn't assign your VM all your cores or it might be nothing left for PVE for hypervising/storage and then the whole host might be slowed down.

Did you maybe disable some virtualization features so Anti Cheat Engines won't identify it as VM? As this might drastically reduce performance when stuff has the be fully emulated instead of being paravirtualized.
 
Last edited:
You shouldn't assign your VM all your cores or it might be nothing left for PVE for hypervising/storage and then the whole host might be slowed down.

Dis you maybe disable some virtualization features so Anti Cheat Engines won't identify it as VM? As this might drastically reduce performance whwn stufd has the be fully emulated instead of being paravirtualized.
Oh, okay, I will give less threads to VM.
Yes, I did install this patch for proxmox anticheat detection: https://github.com/zhaodice/proxmox-ve-anti-detection
EDIT: I'm not sure how to remove this patch as there is no removal documentation. It installs the package: "pve-qemu-kvm_8.0.2-3_amd64.deb",
how can I reinstall the pve-qemu-kvm package without this patch?
 
Last edited:
You shouldn't assign your VM all your cores or it might be nothing left for PVE for hypervising/storage and then the whole host might be slowed down.

Did you maybe disable some virtualization features so Anti Cheat Engines won't identify it as VM? As this might drastically reduce performance when stuff has the be fully emulated instead of being paravirtualized.
Turns out that patch wasn't working since it modifies pve-qemu-kvm proxmox package, but I updated proxmox and the package was overwritten. So I didn't have any virtualization features disabled, so this is not why the VM is slow, I'm gonna try to create a new Windows VM to see if anything would change.
 

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