KVM, virtio and GPU performance factors (non passthrough)

Software & Operating Systems VFIO
1

What is the #1 factor for gpu performance for KVM vms using virtio drivers? I will be accessing the VMs through spice.

I would like to have fully virtualized graphics, but the state of AMD mxgpu isn’t looking good.

So I’m wondering if I should get a GPU with more memory, more clock speed or more memory bandwith? Of course more everything would be best, but I don’t want to overspend given the new gpus always coming out.

2

Fully virtualized graphics are here and the performance is not bad. The question is if you are willing to pay for such solution. Wendel had such a video for vmware + Nvidia quadros.
For SPICE optimizations you can check hints from here: https://www.spice-space.org/static/docs/spice_for_newbies.pdf