VM - Windows server 2025 - Memory used Max

[talinho]

Hi,
I have this Vm with Windows Server 2025,

I’m struggling to figure out how to resolve this RAM management issue. In the PVE panel, it shows that almost all the RAM is in use—and the same is true within the Windows Task Manager—yet there are no actual processes consuming it.
I have installed the VirtIO drivers (version 0.1.302) and enabled the "Balloon" feature, but that hasn’t solved the problem. Below, I’ve provided screenshots of the VM configuration.

 

[UdoB]

and the same is true within the Windows Task Manager—yet there are no actual processes consuming it.

So the question is how you can tell Windows to use less memory than it knows it has available, right?

Usually most OS's will fill "unused" Ram with cached data, after first read from disk. Unused Ram is wasted Ram!

Ballooning will only kick in as soon as soon as the host has less than 20% free Ram available. And then it might trigger the Guest-OS to kill the "wrong" process. Flushing only those caches is the ideal mechanism, but it does not work reliably under all circumstances, as far as I know.

Disclaimer: I am a Linux user...

 

[talinho]

But, with windows server on bare metal, i don't have this problem.

 

[talinho]

 

[news]

then, yes you might delete the vm from the proxmox ve hypervisor.

 

[aderumier]

windows os is filling memory with zero at boot, so the memory is reserved on proxmox side.

only way to trick it is to force ballon/unballon manually after boot to freeup memory.

 

[talinho]

Quindi, sì, potresti eliminare la macchina virtuale dall'hypervisor Proxmox VE.

if i have Proxmox, I should use Proxmox.

 

[talinho]

Il sistema operativo Windows riempie la memoria con zeri all'avvio, quindi la memoria viene riservata sul lato Proxmox.

L'unico modo per aggirare il problema è forzare manualmente l'attivazione/disattivazione del palloncino dopo l'avvio per liberare memoria.

Yes, but the balloon not return the memory to the VM, if the Ram is not used by the host. Why this ?