Womder if its the driver then because using the normal screen mode pref I can test all the resolutions that you get as standard with OS3.9 and when they dont work at least it comes back (think I am running in 640 x 256 laced or something like that) it's purely when I use the cards own resolutions that it hangs. Might try the cybergraphx as well tonight.
Cheers all
John