Must be that Bloodlines is just pants :P
It was bad for me lagging but usually with onboard cards is they tend to cause lag as they cant cope with high level of traffic hence why I asked you.
An idea, check Bloodlines settings and turn off EAX if enabled, also if it is set to hardware mode well you know what im going to say
I have no idea with the soundcard on your mobo, so I couldnt say for sure.