8400gs hardware acceleration

[planetc]

My client attached to my main tv appears to have issues following any type of ff/rew on recordings. It will play perfectly for hours until you use ff/rew and then pans, beit vertical or horizontal become kind of stroboscopic, not a stop start type strobe effect, more of a high frequency fast slow. Audio appears unaffected. Comskip appears to be at least as accurate as it was previously, it's just this wierdness as playback is resumed following the skip. Stopping and restarting playback fixes it every time. Initially I thought it might be relevant to my 6.4.8 upgrade. It was all fine previously but I did make some other changes at the same time as upgrading to 6.4.8. The updated demux filters don't appear to have any effect at all.
After some playing around I found that I could stop this happening by disabling hardware acceleration in the Nvidia Decoder Properties Tab, but overall performance is not as good if I do this. It's close but hardware accelaration has the edge until I do any form of skipping.

This client is a 2.8g Pentium with 1gig of ram. It processes SD content only with output at 720p using vrm9 and fse with the nvidia decoders for video and ffdshow for audio on recordings.
All my dvds use Nvidia and AC3 and are fine, the Avi's use ffdshow and are fine also.
It tried dropping the output resolution to 1024x728 to lower the load on the graphics card, but given that it is only recorded tv that it affects the result was the same, much as I expected.
Is there something anyone can suggest about the hardware acceleration settings within the Nvidia Display Controls that might affect this?

additional info....
I reduced the edge enhancement and noise reduction settings which has not cured it completely, but skipping back and forth a couple of times seems to allow it to settle back down again

[Clift]

Try disabling FSE and using Overlay. 720P should be fine using hardware acceleration on a 8400 GS. I assume MPEG-2, not MPEG-4?