Proxmox 9.1 + Kernel 6.17.13-7 / 7.0.2-2 VirtIO NIC offloading broken in Win 11

[Gia]

• Proxmox VE 9.1.11
• GPU passthrough configured for an NVIDIA RTX 5090
• Windows 11 VM
• Sunshine running inside the VM
• Moonlight clients on LAN

The setup had been working perfectly for months.

Problem​

After upgrading from kernel 6.17.13-3-pve to:

• 6.17.13-7-pve
• 7.0.2-2-pve

Sunshine stopped streaming video correctly when using a VirtIO network adapter.

Symptoms:

• GPU passthrough still works correctly
• RTX 5090 detected normally in Windows
• NVENC appears available
• Sunshine starts normally
• Moonlight connects successfully
• But no video stream is received by the client

Sunshine logs repeatedly show:

Warning: WSASendMsg() failed: 10055

Booting the host again with kernel 6.17.13-3-pve immediately restores normal operation.

Important observation​

Changing the VM NIC model from:

• VirtIO

to:

• Intel E1000e

immediately restores Sunshine streaming functionality even on the newer kernels.

This strongly suggested the issue was related to VirtIO networking rather than GPU passthrough or NVENC itself.

Temporary workaround / fix​

The issue was ultimately fixed while keeping the VirtIO NIC by disabling VirtIO offloading features inside Windows 11.

The following Windows PowerShell commands were used (run as Administrator):

$nic = "Ethernet 2"

Disable-NetAdapterLso -Name $nic
Disable-NetAdapterChecksumOffload -Name $nic
Disable-NetAdapterRsc -Name $nic
Disable-NetAdapterRss -Name $nic

Set-NetAdapterAdvancedProperty -Name $nic -RegistryKeyword "*UsoIPv4" -RegistryValue 0
Set-NetAdapterAdvancedProperty -Name $nic -RegistryKeyword "*UsoIPv6" -RegistryValue 0
Set-NetAdapterAdvancedProperty -Name $nic -RegistryKeyword "OffLoad.TxChecksum" -RegistryValue 0
Set-NetAdapterAdvancedProperty -Name $nic -RegistryKeyword "OffLoad.TxLSO" -RegistryValue 0

After rebooting the Windows VM:

• Sunshine streaming works correctly again
• Moonlight receives video normally
• VirtIO NIC can still be used
• Latest Proxmox kernels work again

Notes​

• Latest Fedora VirtIO drivers were already installed
• Setting queues=1 alone did not solve the issue
• The issue appears related to VirtIO networking offloading on newer kernels
• The problem specifically affects realtime UDP streaming workloads such as Sunshine/Moonlight

Hopefully this helps others encountering similar issues with:

• Proxmox VE 9.x
• recent kernels
• Windows 11 VMs
• VirtIO networking
• Sunshine/Moonlight game streaming
• RTX 50-series passthrough setups