Can't get smooth HD playback with HVR-1600

[SDesforges]

I am experiencing jerky OTA HD video using GBPVR (and the audio loses sync with the video, then quits altogether) with an HVR-1600. The video is less jerky using WinTV or WatchHDTV but still exhibits some of the same behavior. Any suggestions?

System:
WinXP SP2, Dx9.0c with quartz.dll fix
Athlon 64 x2 4800, 2GB RAM, Samsung SpinPoint 500GB, Gigabyte GA-M57SLI
MSI RX2600Pro video card, Catalyst 8.4 beta
nVidia PureVideo, hardware acceleration enabled
On-board sound out via SPDIF

Do I need to provide more info?

[sub]

All I suggest is trying different decoders (incl audio decoders) to see if it helps.

There has been a few people that have indicated they have this problem with their HVR1600 and also mentioned it occurs in WinTV etc, so I suspect there may be some work Hauppauge still need to do.