I have a Compaq Presario V2000, which has only 512MB of RAM. I just so happen to have Windows 7 Ultimate as well, which takes twice that much. I've got a theory that Windows 7 can run perfectly with just 512MB of RAM, here's how I made my discovery: I was given Windows 7 Ultimate for free by a friend, so I went ahead and did a fresh install. I started by installing all my software (Firefox, Thunderbird, etc.). Upon recommendation, I also installed three free pieces of security software: AVG free Malwarebytes AdAware I noticed how terribly slow it was going (I'd have to wait five second to close a tab in Firefox!), and thought that I had a virus. I booted into safe mode, mostly just for the heck of it, and it seemed to run fine again. But after going back into "unsafe" mode, everything went slow again. It took me a while to figure it out, but after an OS reinstall and and some Wikipedia searching, I concluded two things were causing the slowness: The antivirus software was consuming resourcesWindows was loading lots of services I don't needI simply uninstalled the antivirus software and everything went much faster, but still left more to be desired. I also did several things to increase my speed: Switched to Windows classic themeRan CrapCleanerRan Vista Services OptimizerEnabled HTTP pipelining on FirefoxVarious registry tweaksDisabled search indexingDefragment my hard drive on a regular basisDisable unnecessary processes found in the task managerAfter all that, I get reasonable speed, yet it's not quite as good as when in safe mode. At one point I created a log of which drivers loaded when in safe mode, and which didn't. I was going to use it to aid me in disabling all the ones I didn't need to make it even faster. I can't seem to find the log though (I think crapCleaner deleted it lol), but I'll make another and post it up here. I just thought this might help those who are trying to make Windows 7 go faster. I'm also gonna need help figuring out what drivers to disable, more on that later.