I have the garbled screen problem when trying to enable fixed aspect ratio scaling as well.
7900GS
Samsung 931BW (1440x900 native)
I've tried following the instructions in here and playing around with and tweaking countless settings, but have had no luck whatsoever.
Has anyone been able to get it working at all with newer drivers (I'm using 163.44), and if so, would it be too much to ask for a detailed step by step guide?
From what I understand, this whole problem is caused by incorrect
EDID information programmed into the monitor - this is apparently a common occurance. Using something like
Phoenix EDID Designer you can view this information, which I did, and it reports that my monitor supports a resolution of 1280x1024! (which obviously isn't correct, as 1024 > 900). This all starts to make sense after this little piece of information, because when I try and enable fixed-aspect scaling and get the garbled screen, my monitor's OSD reports that the monitor is indeed running (or trying to) at 1280x1024, which the Nvidia drivers think is the max supported resolution (for some reason the monitor drivers don't seem to come into the equation as much when enabling this option).
If some other people with the same problem, and also people who have no scaling issues but a similar setup, could download this little app and report their findings, it'd be much appreciated.
I tried disabling the faulty resolutions and reprogamming the EDID (stored in an EEPROM chip in the monitor) for the DVI port on my monitor (you can do this with a special app loaded onto a boot disk, or with the registered version of powerstrip), but unfortunately it seems mine is write-protected, so I'm out of luck. A lot of monitors don't have write-protected EDIDs however, so it's definitely worth a shot. However, DON'T ATTEMPT IT UNLESS YOU HAVE DONE YOUR RESEARCH AND KNOW WHAT YOU ARE DOING (you could render your monitor unusable, and make it difficult or even impossible to recover). Guides and information
here.
ATI drivers ignore the EDID (at least to some extent), so that's why they seem to have less problems, and reportedly there is a way to ignore the EDID with the Linux Nvidia drivers as well, which allows scaling to work as it should.