Hi Stefan, thanks for testing it!

re:
> [EDIT] also after scaling the bunny up the display problems went away when moving the
> model! I should from now on work with the v4 beta, to see if i can find glitches etc!

There seems to be a problem on older iMacs with the new display engine function in v4 that caches display information on the video card.

I've just received an older iMac over here so I can test it and see about fixing that. But for now you can turn off the caching by the setting described here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=9089.7

- Michael