I'm using a ps2 keyboard and USB mouse. After the update I restored basically the entire extensions folder from 10.5.2 which was probably a stupid idea, so I ran the update again and undid that.

Also the mouse works fine for a couple seconds after booting, but then it becomes laggy and after that, inverted.

And it seems like video effects are really laggy as well, like magnification in the dock and minimizing windows is very choppy.