Overscan works on Albatron GF4 TI 4600 with Conexant-Decoder.
But it doesn't matter if 0.1 or 1.0 - every time the same size.
And 0.0 doesn't even switch it off
I had to switch back to 4191-drivers to get the Overscan-Feature disabled...
Tested with SuSE 8.0 on XP 2400+ with ECS K7S5A
Will try it out with SuSE8.2 this afternoon...