You have the E6400 in your sig?
That only has an 8x multi
Anyway, which one is faster depends on a number of things.
-northbridge core clock speeds/latencies...on P5Bs at least, i know that up to 400 MHz, performance gets better (with higher FSB). Might be similar on the MSI you have; not sure.
-RAM speed. Depending on which dividers you choose to use, you could have various choices.
-FSB being higher is usually better, but again, that depends somewhat on what the RAM is running at.
I'd suggest trying both out & benching to see which wins...