Hauppauge does hardware encoding and pegs the cpu at about 5-15%. ATI does software encoding and nails the cpu at 45- 75% very simple. I have both and there is no comparison in quality.
This link has everything you need to know including which capture card is king(pvr250):
http://www.avsforum.com/avs-vb/forum...php?forumid=26
http://www.shspvr.com/forum/viewforum.php?f=10