I have recently tried XP Mode on Windows 7 and can truly tell you that its horrible.
1st XP mode Doesn't register the system graphics driver or GPU.
2nd it only recognizes a single CPU core not both.
3rd you can't play any games that utilizes 3D effects which is practically almost every game available in Game stores.
Here are some screen shots i have taken on my PC, take a good look at them it will prove my 3 statements above.
"the images are too big for me to post directly onto this thread, so i have put direct links to them".
[SAS]_LCpl_Ade Lance Corporal (LCpl) 22nd Elite Virtual Regiment.