I’ve never been able to get video acceleration without passthrough working on virt-manager. The best I’ve been able to do is use that weird virtual GPU thingy that splits GPUs into smaller sub-GPUs, but doing so turns my laptop into a space heater and hangs the host within half an hour. Partial acceleration of Linux clients is the best I’ve been able to get, but even that was a worse experience than RDP’ing into them instead of using Spice. Installing the necessary guest tools is also kind of a pain, getting resolution updates on window resize working seems to involve three reboots and a dice roll from what I can tell. Hell, I’m still not sure how exactly I’m supposed to run spice-vdagent for graphical Linux guests (I can’t find a systemd service file, but surely my workaround of launching it in XDG autostart on login can’t be the intended solution?).

I use virt-manager for most VMs, and Virtualbox and its weird hypervisor generally sucks across the board, but for the people who just want a quick VM, Oracle does a much better job.