I am running CGMiner. I will try that suggestion.
One more thing, for some reason CGMiner isn't using all of the clock speed that I set in either TRIXX/AfterBurner or in the command line argument. I set it to 1200 mV, 950/300 but I get only ~250 mh/s. GPU CAPS viewer shows that the Max clock is indeed 1200 mV and 950/300, but the Current clock is back to default, 1163 mV and 800/1000. I have Catalyst 12.1, so I'll upgrade and see if that helps.
EDIT: Upgraded to Catalyst 12.6, everything seems to be working great now. Getting 305 mh/s on my 5830 at 1200mV, 975/300!