How big a performance increase will I see?

[InorganicMatter]

Coming from this:

P4 2.6GHz non-HT
D850EMVR Motherboard
768MB RDRAM
Radeon 9600XT

To this:

Pentium D 3.0GHz
ASUS P5ND2-SLi
1GB Corsair Value Select DDR2-533
eVGA 6800GT PCIe

Intel/nVidia ONLY.

 

[IceDigger]

Big difference in games. You should be able to crank the games up to maximum now.

 

[shadowbreaker513]

A big one, though you may be a tad CPU limited.