I've somewhat stripped down my OS. I have an older P4C800E-Dlx Mobo, with a 2.4C proc and 2 Gig ram.
It runs mach3 on a Win7 OS. I shut off all the windows eye candy, and power saver options.
Over on Black Viper's website, he lists all the widows 'features' you can live without,
and the reprocussions of turning them off.
http://www.blackviper.com/I have Win7 32bit and I've set up Windows to a Safe/Tweaked system, and runs much faster/smoother
then before, I also set Mach3 one level higher on the CPU priority list.
For this older system, it runs pretty good with Windows 7.
I just have to replace my BIOS battery now! LOL ;o)
Check out his site, its full of some great information.
Chris