Windows 11 VM extremely slow

[trigg3r]

I have Proxmox 8.3 on a HP Proliant server with RAM: 128GB and CPU: 48 x Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz (2 Sockets)

No matter how I tried to configure a VM with Windows 11, I always get an extremely slow machine.

I use VirtIO drivers for disk (on local zfs filesystem), network and balloon.

For CPU I tried setting Type to host/qemu64/x86-64-v2-AES; I tried enabling and disabling "Balloon"; I tried setting Machine as q35 and i440fx ... (different combinations of these)

In all cases I get a very slow machine. The strange thing I notice is the RAM consumption: Proxmox shows a RAM usage of 90% while from inside Windows the task-manager shows a RAM consumption of 10/20%.


What can I try to do?

 

[_gabriel]

Proxmox shows a RAM usage of 90% while from inside Windows the task-manager shows a RAM consumption of 10/20%.

it's expected from point of view of PVE. Turning on Ballooning will hide cached / reserved RAM.

I bet on slow storage.
Windows 10+ as VM require nowadays ssd, and enterprise ssd if ZFS.

+ Windows 11 24H2 run in nested virtualization, for their VBS, if you use "host" vCpu type.
Disable VBS to get back Win10 and Win11 23H2 CPU perfs.
You can check if active from msinfo32.exe

+ On old CPUs I disable mitigations, or they run too slow.

 

[cwt]

Slow storage in combination with a relatively old CPU from 2016. Especially with Windows 11 the CPU is some kind of handbrake.

 

[trigg3r]

@_gabriel @cwt Thank you very much! In fact, storage is done with HDD....I will go in depth with Gabriele's suggestions (I don't use Windows much and honestly I wasn't aware of these things ... thank you again!)