Almost everything.
To use that CPU you'd need a new motherboard. That motherboard would require DDR2 or DDR3 RAM. Almost undoubtedly you have an AGP video card, and that will be next to impossible to find on any modern motherboard, so you're looking at a new video card. Then your hard drive(s) are probably IDE, and finding an IDE controller on modern motherboards will be exceedingly difficult as well, so you'd be looking at a new hard drive or an IDE controller PCI card. Then with such a massive change in hardware, you'd be looking at completely reinstalling Windows.
So basically you're looking at a whole new computer. You might be able to salvage the case, but that's more or less it.
hey, im thinking of upgrading my cpu; here are my necessary specs:
AMD Athlon XP, 1250 MHz
MS-6712 (Motherboard)
VIA VT8377 Apollo KT400 (Motherboard Chipset)
768 MB DDR SDRAM
id like to upgrade to AMD 3000 or more, do any of u guys know what else ill have to purchase besides the processor in order to upgrade this? (ex: motherboard perhaps).
thanks in advance.
harry
www.seotrump.com

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