I recently reinstalled XP and enjoyed snappy performance up to a point. It's not too slow now, but i notice i am not enjoying the speed as much recently. I believe the turning point was when the partition i devoted to the OS became too full. All was well when i was using only about 2.5GB of the 4GB i devoted to the OS (and several core programs, runtimes). I would use Piriform Defraggler every time i booted up, and because i could defrag in about 15 seconds, it was no problem. At some point, about 3.1 GB full, things started slowing down, and it takes me way longer to defrag anymore. I have still 20% of the dedicated drive free, but the defragger erroneously thinks i have less than 10% available when it tries to defrag, and complains about it. I've been using CCleaner both before and after the slow down and can say that while it's a good utility, the problem is more related to space and organization. I'm not yet an expert admin, so i don't want to make definitive statements here. I'm open to the idea that excessive surfing and/or the acquisition of a new breed of gangsta virus might be onboard and contributing to the slowdown. I don't use any anti-virus software because for one thing, why did i completely update XP with service packs and security hotfixes if i can't feel safe? And in my experience, modern anti-virus software functions like a virus with the limited 256MB memory i've got,and constantly pulls CPU power for it's monitoring processes. For this reason, for example, i installed and de-installed Microsoft Security Essentials and outright reject the bloated size and corresponding demands of today's popular anti-virus software. Instead, i just use the relatively small demands of SpyBot Search and Destroy, and cross-my-fingers. Besides all that, i don't use anti-virus because i've got a clean image of my fast set-up backed up on external storage, so i've got a relatively accessible restore point if i really want. The problem is i've gradually added programs, certain of which demanded to be installed on the C: drive, where my OS is at. Those and other programs there like to automatically store related data on that drive in their home folders. So i've been experiencing space creep. Probably i need to rethink which programs (of about 27) really need to be close to the OS (on the same drive). This is all i've got to offer you at this time:
A.)Partition, leave the OS plenty of room,
B.) build things up the way you like,
C.) be careful about what programs you install on the same drive as OS,
D.) and back everything up (when it's fresh) on an image that you can restore later. This is also insurance against virus.
I don't think you really need a lot of memory to experience snappy speed because i've experienced it without a lot of memory. Just have to be smart about a few things.