i'd have to say no....i own an mx300 and ran it on an mpv3 and 686a southbridge (both via)...works flawlessly...
i think the troubles people are having are soundblaster DOS emulation related...just disable (or don't install it during the initial driver installation), or they're using the wrong driver versions...
note: the WDM win2k drivers suck massive sh1t...they function fine for everything but 3d audio (a3d)...which is the major merit of the card - it's superb 3d positional audio....