Did i make a mistake Buying Crucial Ballstix PC 6400?

Hello , i just baught Crucial Ballistic DD2 2gigs PC6400 few days ago and i just seen the Crucial Ballistic DDr2 PC1066. are the two that much difference between each other? or did i make a mistake going with the ddr800

Fast memory, don't worry about it.

you'll be fine. You can overclock the memory to 1066.

BOTH sets of my Ballistix PC2-6400 can run DDR2-800 at CAS 3 or DDR2-1200 at CAS 5. No mistake there.

In dual-channel mode, you won't get ANY performance benefit from running the memory clock at higher than 1.5x the CPU FSB clock. Gigabyte calls the ration "3.00" where they refer to memory data rate versus CPU FSB clock rate.

So basically, running the memory at Gigabyte's "3.00" setting will put your memory speed at DDR2-800 (400MHz clock) with an FSB-1066 processor (266MHz clock). And since the memory you've chosen overclocks well, you can get to FSB-1600 (400MHz clock) while still keeping the memory at gigabyte's "3.00" setting.

Wow, good question! I've only used the 2x 1GB kit!

;}~

Most of the people here are running 32-bit operating systems where anything more than 3GB total memory doesn't make much sense. Finding a user of a 2x 2GB Ballistix kit could take a while.