OK...let me get this straight: If you have a mobo that supports 800Mhz FSB; then your prossecor needs also to be 800Mhz FSB to be able to run an DDR333 (@320Mhz) and DDR400 But if you mobo is 800Mhz FSB and your prossecor is 533Mhz FSB then you can only run DDR333. Right? I´m all confused in this matter... Tryied to understand this subject from this page: http://www.msi.com.tw/program/products/mainboard/mbd/pro_mbd_detail.php?UID=434&MODEL=MS-6758

I think you're mixing your mental fours. "If you have a mobo that supports 800Mhz FSB; then your prossecor needs also to be 800Mhz FSB to be able to run an DDR333 (@320Mhz) and DDR400" The processor is not really as important as how you configure your memory. the CPU will always run faster than memory therefor it will keep up. In Bios there is a multiplier value that matches the memory buss speed to that of the processor (actually by adjusting the CPU speed). Overclocking manipulates the speed of the processor in this way. The actual value (not overclocking) is: rated processor speed divided by rated ram module speed. for performance you'd choose the fastest modules you can get since the FSB is capable of operating up to 800Mhz. with 2 modules you have the option of running them in an serial way, 256Mb + 256MB = 512 MB total or in a parallel fachion 256MB + 256MB = 256MB (but you get twice the bandwidth.) the manual says there are 2 dual slot banks(channels A & B). you load the modules like this: A1 + B1 (Serial) A2 + B2 (Serial) or A1 + A2 + B1 + B2 (Parallel and Serial) Note that in each case both channels have at least 1 module. You can't do this: A1 + A2 -or- B1 + B2 Either way it will be a screamer so think about attaching handles to the monitor to hold onto.

skuli that board you're looking at has some weird incompatibilities listed there. one note on the above post: "or in a parallel fachion 256MB + 256MB = 256MB (but you get twice the bandwidth.)" in this case 256mb+256mb=512mb as well, plus you get twice the bandwidth.

I see... Thanks RayMan and johnoh

Basically - the motherboard won't let you have that RAM be that fast. For a 533FSB CPU, the motherboard chipset won't let you use DDR400. You could still use DDR400 and run it at DDR333 speeds... then if you upgrade to 800FSB, you've already got the best RAM to use with it.