When I tumble objects and change parameters my objects behave as I would expect, but if I scrub the thumb along the time-scale it takes an eternity to update. I can only imagine that I have altered a setting for display, have a bug in my OGL, or my graphics drivers/card is at fault - I've not had this problem with houdini pre 8.0.41 - any ideas? I even un-installed and re-installed houdini its that annoying.
I'm running XP home with an athlon processor, and Gforce3T500 card.

there is a thread somewhere on the forum about nVidia graphic card and best driver version for Houdini. Just do the search.