What are the benefits of PCI passthrough?

[smizzlov]

I have a high-level understanding of the PCI passthrough feature of Proxmox, but I'm still wondering what the benefits of it are.

My guess is that it helps with approximating a bare metal experience when using a VM with desktop environment?

Can anyone elaborate?

 

[dcsapak]

there are multiple reasons why someone might want to pass through pci devices.
for example:

having a 'gaming' or 'gpu render' vm where you need gpu performance/features (e.g. cuda) inside a vm
passing through network cards to get more speed (since you skip the host kernel & network setup)
virtualizing a nas where you pass through a SATA/SAS HBA/Raid controller
and many more

basically if you want to utilize physical hardware inside a vm for any reason (performance/security/isolation), you could use pci passthrough