The MB has a maximum FSB of 533Mhz. There are several different FSB speeds in the s478 CPUs, ranging from 400Mhz-533Mhz-800Mhz. Your MB will support 400 or 533 FSB processors. To identify which chip you have, clean the thermal media off of the heatspreader of the processor and there will be a line that looks somewhat like this "3.00Ghz/512/800/1.425V." The third number indicates the FSB. If it is 800, then it will not function with the chipset on that MB and replacement of the MB will be the only option to get it to function. You can also look up specifications by S-code. Google for the code stamped below the long string. It should look something like "SL6GS."