I don't think the performance is so differnet after boot. Debian stable aka etch is just older, or you use Kanotix which is etch + lots of new backports. But don't think that you gain more speed, your gfx cards is very slow, so when you need gaming performance put in a faster one (9600 GT or similar). RAM is also a bit low for some (commercial) games, not for standard office/internet usage. Maybe a newer kernel can improve hd performance if that is a problem.
hdparm -tT /dev/hda
hdparm -tT /dev/sda