This old chestnut. Maybe a sticky is needed.
AVS is based on your CPU speed (not your graphics card) and I have a 1.4Ghz Ath and at Full screen the more complex presets, UnConeD, etc. run at about 4 fps (Frames Per Second) at 800x600x32.
The more complex the preset (normaly the beter looking ones) the slow AVS will run.
To make this a lot quicker you can turn pixel doubling on (make it run at half resolution) or reduce the resolution until you get a reasonable frame rate.
If you want something that runs faster try a different plug-in like Winamp's own MilkDrop at
www.nullsoft.com/free/milkdrop
This will run at a decent frame rate full screen. And click on the forum links or
www.milkdrop.co.uk for more presets. Though not as much variety as the AVS presets.
Plug over.🙂
Hope it helps,
Rovastar