I’m not quite sure how you
I’m not quite sure how you mean lagging/stuttering, but my HTPC has really been bugging me as well. And it has been a stuttering issue as well. Sometimes I notice a slight (and sometimes it is very slight) stutter on bluray and recordings. At times I have seen the stutter very pronounced. Netflix is nearly unwatchable due to the jerkiness, but I’ve read where many people have this problem. I haven’t been able to pin point the cause. I don’t know if it’s because of standby, Radeon drivers, the 6570 its self, or some other corruption. My system was pretty smooth when I was using a 2600xt, but then I couldn’t play 3D bluray. I’m not sure for the small percentage of 3D that I watch it’s worth everything else being “broken”.
Also, I’m not using a receiver…at least not with the HDMI. My HDMI goes straight to the TV. I have a 6570 video card. Again, I’m not sure if we are talking about the same kind of stutter but I found your problem interesting as they do sound similar. My sound is also fine; it’s just the video that’s not.