Well how do I start?
"Huston, the Eagle has landed"
I think this is the first time in the last 12 month since I "felt the urge" to do this, that I feel that I've done it, that VGA Passthrough is not only possible, but it also stable enough (99% of the time, although a reboot is sometime necessary) for daily use:
- USB passthrough is working fine
- the sound controller passthrough is also working fine
- VGA passthrough is alright and well I just played Crysis 1280x1024 all setting Ultra High without any problems.
Once you have the hardware, the knowledge is out there (and here), you just need to play with it and make it work for you.
The latest version of the guide is at: https://docs.google.com/document/d/1ef_nfl652L0HLn_wGvnpgjsBJd9LZzaV_-rIcEEoK8Y/edit
Proper benchmarking is hard, and I might have done something wrong, because almost all the benchmarks are showing >90% of native Windows performance, except Crysis (I played it in the vm with all setting on ultra high and it was fine, at least in my humble opinion, so i don’t know why I got so low result in the benchmark ) and Stawker Call of Prypiat (this is a total mistery).
You can find the results at: https://docs.google.com/spreadsheet/ccc?key=0Aryg5nO-kBebdFdOLU1Yc0trT29JdUxac21QcXg3Qnc#gid=6
You can always do your own ;)
From the last post about VGA passthrough.
Xen benchmarks, well I think I've had enough of using 'sombody's else code' for the time beeing, but I wouldn't exclude a Xen comparison sometime in the future, if I have the time.
https://help.ubuntu.com/community/KVM/Installation this + intel_iommu=on to grub (grub2-update), and not installing ubuntu with uefi should be the same thing as fedora, I don't have the time to test ubuntu right now.
Check how many cpus does the VM see? If you get the same bad performance no mather what video card you use, maybe the game is cpu bound that's where I would start.