tweaking video performance?

I’m testing Whonix 13 on both VirtualBox and KVM on the same virtualization-enabled machine. On the KVM install I notice a slight, but definite lag in video performance on the basic Workstation interface (no extra apps running). Is tweaking the vram and/or vgamem advisable? If so, can anyone suggestion a rule of thumb for both selecting an optimal value and editing the default configurations? In other words, how much memory should I allocate and what is the best means by which to configure it (virsh -c qemu:///system edit … )?

The following link is perhaps the most insightful piece I’ve read so far … any thoughts or recommendations?

Is the problem you’re seeing a Whonix 13 one - has it worked better before?

Its not advisable to enlarge vram than the default. After playing with it I realized it consumes more RAM with no perf benefit so I reverted to default values in the upcoming Whonix 14. Its possible to watch hi-def vids in the WS but not fullscreen.

I suspect it is a KVM issue, as I see the exact same lag-effect on Windows 7 installs, comparing vBox and KVM. I have not actually tried full-screen playback on either Whonix or Windows via KVM, as basic interaction with the desktop is still a question. I did push the vBox Video Memory field up to 128 MB, and I it runs either OS very well. However, I don’t understand what that vBox setting actually corresponds to in the KVM configuration (i.e., vram, vgamem …?).

I might add, this same machine offers good performance running Qubes OS, so I am a bit frustrated that I cannot get KVM up to speed.

Ah that must be another problem then. Please install the qxl-xorg-enhance package as described here: