Well, try this!!!

.PCI master read caching, default setting=Disabled
.PCI master time-out, Default setting=1

Setting above options to Disabled/3 will lead to the same result with VIA Latency patch V0.14 and may help SB Live 5.1 sound issue. .

VIA Latency patch V0.14:

http://www.viahardware.com/download...atency_v014.zip