I've tested up to the 1600x1200 resolution with GL Hexen (using Viewsonic G90f monitor)

Tested using FooBillard v3.0a for MorphOS - no major issues to note!

1280x1024 (all graphics detail high or ON)

Pegasos II ODW details:
MorphOS 1.4.5+ATI 3d drivers+ft2.library patch
(1GHz PowerPC G4, ATI Radeon 9200SE, 256MB RAM,40GB HD, DVD+/-RW)
SmartFirmware v1.2 (20040810...)

~K