Doug,
Your signature says you are on a Mac. This business of going to manufacturer's web sites for drivers is a Windows thing. On Mac, Apple provides all drivers as part of the OS, bundling any updates into the next release.
If you've gone to the Apple menu and done a Software Update... and installed everything available, then there's not much else you can do from a driver standpoint. (Your signature says 10.6.6, but 10.6.7 is the current OS X version - and the 10.6.7 release was advertised to include some updated graphics drivers.)
This does not sound like a graphics issue to me anyway.
There are some strange behaviors on Mac that Graphisoft is aware of, such as rubber banding not being visible if you switch applications while ArchiCAD is launching. (Hiding ArchiCAD via cmd-H and then bringing it back to full screen resolves that one.)
The fact that you installed 13 and it is acting up also seems really odd.
By any chance, do you have a second monitor plugged into your mac, but which is powered off? If so, either turn it on, or unplug it. That causes erratic mouse behavior which could be related to your issue
My last idea for the day on this one is that you have some other program or utility installed on your Mac that is causing the issue. Create a login for a new, non-administrative, user. Log out and log in as that new user and see if the problem persists.
Cheers,
Karl
One of the forum moderators
AC 27 USA and earlier • macOS Ventura 13.6.9, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB