I have R5C7 installed on with a 350 & 500; I just got home and had left the unit & TV on and it was stopped with a kinda' bluish screen; I backed out of "Watch TV" and went back in and I'm seeing the same kind of thing now, not really bad, but just little pieces dropping out every now & then, picture jumping occasionally.
Only thing I've done was adjust the offsets in setup > TV > playback, and that was just a slight amount, as the picture was a little too big for the screen.
I'm using the 0.4.4 IVTV drivers, as I read the newer ones cause problems.
Using an overscan of .7 in the XFConfig with S-Video out of the 350, composite in to both cards.
I had a good picture out of the 350, just needed a little sharpening, the 500 gives me a snowy, choppy picture on both tuners. Thought I just needed to fine tune the 350 a bit, then work on the 500, now it's back to the 350....

'Sorry, this was supposed to be a reply on randomhtpcguy's post; somehow it got orphaned.
Thanks.