Does hardware acceleration even work (properly) if you run Win7 in a VM? I know vmware supports "some" version of Direct3D, but iirc it was a relatively low version - and I bet there's a speed hit as well.
VirtualBox uses hardware acceleration, (still listed as experimental): DX 9.0c (4.09.0000.0904) in my XP VM
The W7 VM says it's DX11 and Direct3D is enabled but there's no AGP Texture Acceleration.
I'm guessing with that disabled, any game is going to run pretty rough.
Just as a test I installed Serious Sam II, (original version, not HD - so not the latest in gaming requirements necessary), in a W7HPx86 VM, (2xCPU, 4GB), and besides the mouse interaction being hyper-sensitive the actual framerates were absolute crap - estimate at around 10fps (if you were lucky).
Note, this was running the VM on my W7x64 machine, so as SJ said, running it from XP is probably going to fare much worse.