Screen resolution wrong with dual GPUs.

Tim

I recently put in a second gpu (a 4850 to go along with my original 4870) for folding.

Once I did this, and made the jumper for the second GPU, I can't get any more than 1024 by 768 resolution on my 204B 20" monitor, which goes to 1600 by 1200. This isn't a problem, except that when I play WoW it does not even give me the option for anything more than 1024 by 768 and it looks terrible at that resolution.

Plugging my main monitor into either gpu still identifies it at monitor #1.

I have monitor #1 set as primary, so why does it all of a sudden go no higher than 1024 by 768? The pc has been restarted numerous times, the dummy plug has been switched (that was the only way to make my monitor appear as #2), and I see no reason why this monitor won't show anything higher than 1024 by 768 now.

I shouldn't have to live with the monitor set as #2, I need to make the Display Properties window give me back the higher resolutions. This all started once the second gpu went in and I had to extend the desktop to make it work right for folding.

shwaip

Why do you need that resolution? I mean 1024x768 is the same as 1600x1200. They both show colors.

Ryder

You enabled Crossfire, correct?

Do you have both monitors connected to 1 card?

Tim

No the crossfire is not enabled because both GPUs are folding, the 4850 is only in the PC for more folding. There is only 1 monitor. And a home made dummy plug in the 4850 with the 3 resistors so I don't have to have an actual second monitor hooked up.

Here's a strange thing - everything I've read says that with XP, you do not need to use the dummy plug for the second video card. Yet in my case, it HAS to be in or the second folding instance will say there no driver or the gpu is unsupported.

And then the display properties show monitor #1 only goes up to 1024 by 768, and monitor 2 (which does not exist except for the dummy plug) goes to 1600 by 1200.

Instructions in the folding section say not to enable crossfire so both GPUs can fold their own work packets. As part of getting the second GPU folding, the desktop has to be extended to the second monitor. That's where the troubles begin.

Shwaip - are you trying to use my logic on me?

Tim

I tried putting in the crossfire bridges, that didn't help. Someone on another site suggested putting the dummy plug in the 4870 along with the monitor plug, that didn't help either.

I might try putting the 4870 in the slot furthest from the cpu, I don't know what else to try. It sure is frustrating, though.

RichD

You probably have them set to mirror the displays. ie you have the same picture on both and therefore you can only get the highest resolution of the lowest spec card. Under the display setting you should be able to change it to extend your desktop. This will then let you change the resolutions of the two displays independantly.

edit...

This might not quite be true as this applies to two displays on one card. Not sure what will happen with two separate cards.

Tim

I tried putting the 4870 in the farthest from the CPU slot today, with the 4850 in the first slot. Didn't help. I tried several CMOS resets, didn't help.

If I take out the 4850, or if I just use the 4850, I can get the resolutions normally. But with 2 GPUs in it's messed up. In Display Properties, monitor #2 can have any resolution it wants, but monitor #1 (which is the only monitor I have) has only a choice of 800X600 or 1024X768.

Motherboard is a Gigabyte EP45-DS3R.

During the one time I actually had 2 monitors hooked up, they weren't mirrored, you can move the mouse cursor from one to the other and they can show different things independently.

Maybe there's some setting in ATI's CCC that needs changed? I'll look.

RichD

It sounds like a driver issue. might be worth looking in device manager at what driver each card is using when they are both plugged in and when you only have one plugged in. If it changes you can do a maunal driver install with the correct driver file.