guest windows 7 becomes slow without reboot

[hxxxrz]

I have guest win7x64 on debian9x64. Windows becomes very slow if I don't reboot it for a day. Is it a proper behavior for a virtual machine?

 

[mbaldini]

I have various Win8, Win2003 and Win2012R2 VMs on Proxmox from 3, 4 and 5 and none have a slowdown, I keep them always turned on.
Perhaps you should post some details on your setup, hardware spec, filesystems, VM configurations and so on