I gave myself an early Christmas present and maxxed out my ram. 2gb to be precise. My old computer seems to be running faster than ever. It looks like a wal-mart relic from 2001 but it has 2ghz P4, 160gb hd and now 2gb memory. woo-hoo I can avoid obsolescence for another year or so (I hope!) I also upgraded my girls computer but all they had available was 1gb. Surprisingly it came as one 1gb stick (shoulda bought 2). So I stuck the original 256mb ram in the other slot so it has 1256mb of ram according to the system stats, is this OK to run like this or will it slow it down somehow?
Unless you're running some pretty ram intensive applications, i.e photo editing(and i'm not talking about simple crops), video editing, the latest games... 1 GB is sufficient for XP. Even with 1 GB you should be fine, that''s all I have and I do run a lot of applications that require a lot of ram. That's assuming you're running a clean system without a bunch of crap installed.
I opted for 2gb because I have a few things running that suck up memory. I always have UPS worldship and some other shipping/accounting software going so just browsing the net I'm using 400mb, 512 did fine actually except when I tried to play games like "DOOM" so more memory helped crutch my older video card. No way am I going to buy a $500 vid. card, I'll buy a PS3 first.