High Frame rate dropped

I am trying to reinstall my AIW 7500 into an upgraded system.

I have a 1.3Ghz Celeron, 256mb, Windows XP with a fresh install. This is
upgraded from a 700Mhz Celeron.

When I run the video capture on DVD I get about 15% of the frames lost and
when I run TV on demand the picture playback is not very smooth. With the
700 I could capture DVD quality without any loss and tv on demand was
acceptable.

The configuration test utility tells me everything is fine except the
DirectX 8.1 is not proerly installed. I tried reinstalling and then
upgrading to 9.0 but stil get the same message.

Can anyone help me with some ideas as to how to get back to the performance
I enjoyed with a much slower CPU?