the 2600 blows
x1950xt
thing is, you wanna make sure that ur CPU is good, and ur ram
if u wanna take full advantage of ur x1950, be sure to havea good Core2Duo, or an Athlon X2 4800+ or higher, comboed with 2-4GB of DUAL CHANNEL DDR400, or DDR2.
^^ in fact, i think DDR1 bottlenecks C2D's, if im not mistaken, although since its an X1950 and not an 8800, i dont think this effect will be so dramatic
otherwise itd be a shame to waste ur money on such a nice card with a bad CPU.