Originally Posted by Ste
Some boards will allow you to run faster than your FSB. This isn't generally recommended though as an Intel's Ram communicates with the CPU down the FSB. Therefore, running Ram faster than the FSB rate generally doesn't help very much.
I don't think he was asking about running the RAM faster than the fsb, just running anything greater than DDR400 on his Intel setup. In any case, yea, you can run RAM that is faster than DDR400 on your system. Since RAM faster than DDR400 is not officially recognized by JEDEC, you have to manually set your fsb to match the faster RAM by leaving the RAM/fsb ratio on 1:1 and just up the fsb.