|Can you explain more? An ATI IXP 400 looks to be a south bridge chip which tells me nothing and doesn't help you.|
Rather, what's the make and model of your motherboard. To search yourself (because it's easy) type it in Google and looks for the Specs, it WILL tell you the max amount of RAM your computer can take. If you have WindowsXP 32bit, you'll max at 3.5ish Gig's of RAM.
"How much ram is too much ram?" That depends what you're wanting to do. What are you wanting to do?
AMD Phenom II X2 550 @ 3.11
Patriot PC2-6400 4Gig
Seagate 160Gig SATA
Seagate 320Gig SATA