Radeon and DOS refresh freq.

Hi,
I just exchanged my older GeForce for a new Radeon 9800 pro. I have
noticed a very strong descrease in the quality of the standard VGA
display, like in DOS text mode. It looks like the nVidia cards use
60Hz refresh, but Radeons only 50Hz? Is there any hope of changing
that?

Thanks,
Marcin