Is your PVR 150, 250, 500 etc picture quality relatively the same quality as the on board tuner of your TV? Mine seems quite choppy and pixelated, and I am not sure if its just the tuner card or if it is my md/core. It would be tough for me to believe that it is my LMCE setup since I can stream multiple movies at a time with no problems. I wonder if I have a bad card or something.
my setup is a pvr 150 in the PCI slot on my core (Dell optiplex, 3ghz, 4gb ram, 100/1000 switch) (MD is 2.8ghz, 1gb ram, motherboard VGA output) tuner card is using the coax input. It really has problems on sports or any fast moving scenes where the camera is scrolling across an image.
My MD currently only has a 10/100 Nic, but I would think that a DVD quality movie would be more data than streaming SD TV. I am just using VGA output of the MD, maybe this is a problem. Although once again it plays movies without a hitch.