Interesting. I suspect that everything worked ok in 3123 since I recall watching at least one DVD at fullscreen and I am sure I would have noticed the degradation.
I tried downgrading back to 3123, but couldn't manage to get X to start up right.
I don't think it is a codec or player issue since the problem occurred both with DVDs and with avifiles and both with mplayer and with ogle.
Also, I assume it is not a direct hardware problem, since DVDs play just fine under M$ XP.
This leaves me with the suspicion that it is either a driver or a configuration problem. Since my XF86Config is pretty vanilla and since I have a standard RH8.0 X11 installation, I suspect it is a driver issue with scaling.
I guess I should try one more time to downgrade back to 3123 to test the hypothesis.
Fedora Core6/Linux 2.6.x
nVidea driver: 9631
Asus P4PE motherboard
Intel P4 2.8GHz
1.5GB PC2700 DDR Kingston
Leadtek Ultra A250 GF4 4600 128MB with VIVO/TVO
WinFast TV2000XP Deluxe
Dell 1901FP 19" LCD
Antec 400W Power Supply