Memory usage discrepancy

[Larrymetos]

Newbie question: The Proxmox server Summary shows one of my Windows 11 VMs with a memory usage of 15.05 of the 16GB allocated. However, when I console to the Windows 11 system, go into Windows Task Manager, and look at memory usage, it shows only 2.5 of the 16 GB is being used.

Can anyone explain this memory usage mismatch?

 

[UdoB]

This has been discussed several times.

In a nutshell: PVE gives 16 GB to Windows and these 15/16 GB are currently used - as they should!

Windows uses ~13 GB to cache data. Windows knows that this Ram could be used for applications by dropping the cache. That's why it tells you "13 GB Available".

PVE cannot know that! Try to install the Guest Agent! And then compare the presentation...

For reference: https://pve.proxmox.com/wiki/Windows_10_guest_best_practices

 

[BobhWasatch]

Also, if you have any kind of PCI pass-through enabled on that VM all memory must be allocated on VM start. This is because DMA can access any part of the guest's memory at any time.