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Old October 3, 2009, 04:29 PM
trodas's Avatar
trodas trodas is offline
Join Date: Feb 2008
Location: Czech republic
Posts: 352

My System Specs

Question DVI output & max 60Hz refreshrate

On DVI was possible only 60Hz. At least my old beta ones, 45.28, can't seems to show more that 60Hz on LCD monitor pluged into the old 5600XT cardie using DVI connection - while the same drivers did not have a problem with 100Hz refresh on CRT.

After some Windows install tweakings, I decided to "give it a try" and check out 53.03 WHQ drivers for the weird "60Hz only" problem. Much to my dismay, the "60Hz only" problem seems to persist.

Dunno why. Even in lower resolution the driver "force" 60Hz. Is there ANY way to lift this limit? Im affraid that if I use ReForce and force the refresh higher, then upon reboot I got BSOD "inacessible device":)

Not that there is anything wrong with BSOD, yet I would rather see another result :)

Forceware (I still like the old Detonators better...) 81.95 WHQ - still 60Hz only:

I beginning to feel that the problem is "somewhere else". I checked the bios setting and yes, there it is - the DDC scanning was skiped on the boot, so it might do somehing bad. Changed it, but no difference... Maybe reinstall again?

Is there any way to check if the GFX card bios properly reporting the capability of more Hz or not? The problem was not when I used the same card with VGA output and CRT monitor, yet using DVI and LCD monitor I running into a 60Hz wall ... :(

Looks like Linux users find a way:
"AllowNon60HzDFPModes": some lower quality TMDS encoders are only rated to drive DFPs at 60Hz; the driver will determine when only 60Hz DFP modes are allowed. This argument disables this stage of the mode validation pipeline.
Now let's hope I can find a way to fix this problem in Windows too...

I reasonably believe that since the 5600XT can do 2048x1538 pixels in 80Hz refresh, then it sure can do 1280x1024 in 75Hz. eVGA says 5600XT it can do 150Hz in 1280x1024:

As the Linux solution suggest, the drivers cap the refreshrate to 60Hz, because they detect "some lower quality TMDS encoders are only rated to drive DFPs at 60Hz"... But since the very same TMDS encoder can give me output resolution of 2048x1538 pixels in 60Hz refresh, then sure as hell it can give me 1280x1024 in 75Hz. As on Linux :)

Now the question is only how to duplicate the Linux nVidia drivers option "AllowNon60HzDFPModes". Anyone can shred some light at this?

I, personally, see only two ways.
1) change/patch/modify the drivers somehow to allow the non 60Hz DFP modes even on 5600XT card
2) change/patch/modify the GFX card bios to not report lower quality TMDS encoder, thus allowing drivers to set up higher refreshrates

Who can help me to get same results on Windows as on Linux are possible?
"It is dangerous to be right in matters on which the established authorities are wrong." - Voltaire
...just keep folding, just keep folding... :) my config
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