6950 crossfire limited to 1600x1200

Hello,

I could use some help here. My new PC has two ASUS 6950 in crossfire. The display's maximum resolution is 2560x1600, but windows will not allow me to raise it past 1600x1200. Any idea what I'm doing wrong?

I'm new to the crossfire system, so I may be missing something. Each of the video cards has two DVI outputs, and only the DVI ports of one of the graphic cards will display something on screen. But regardless of the DVI output I use on that card, the resolution is limited by windows to 1600x1200.

I have the latest AMD drivers, windows 7 64 bit. The monitor's settings tell me that the input is indeed 1600x1200 and that it can go up to 2560x1600.

Any help would be greatly appreciated.
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More about 6950 crossfire limited 1600x1200
  1. you can try running just 1 card to start with (no crossfire)

    but i doubt thats the issue.

    its normal that the outputs on the 2nd card dont work. as soon as crossfire is enabled they are disabled.

    what model & brand screen do you have.
  2. The screen is a Dell U3011. It was running fine at 2560x1600 with a single 5850 card on my previous PC. And I didn't have to configure anything, windows immediately set the resolution to max. Now with two 6950 in crossfire, I'm stuck at 1600x1200.

    I have the latest drivers for both the monitor and graphic cards.
  3. I'm trying a single graphic card now as you suggested, and the maximum resolution is still 1600x1200, as well in windows settings as in CCC. When I go in the monitor's OSD menu, I see:

    Resolution: 1600x1200@60Hz

    Maximum Resolution: 2560x1600@60Hz

    This is really frustrating!
  4. I have a hazy, vague memory of having this problem myself once with a build. If I recall, buried somewhere in CCC there is 'resolution limit' option and I had to increase that before I could select the resolution I wanted...
  5. Like jay_l_a said, I'd suggest going into CCC and checking out the display options and see if there's any tweaks you need to make in there.

    Also, make sure you install your monitor's drivers (if it says "generic PnP" or something, it's not installed)
  6. Thanks for the suggestion. Any idea where I can increase that resolution limit in the CCC?
  7. Also, did you change cables?
  8. The display and cable are brand new, and they work fine on my old PC which has an older ATI card.

    Funny fact though: the drivers for the monitor on that old PC report "generic PnP" and are older than those installed on the new one. I'll try uninstalling the drivers on the new PC and see what happens.
  9. Nope, didn't work. I still have the problem, regardless of the monitor's drivers. :-(
  10. Do you know if your cable is DVI-D, DVI-I or DVI-A? Basically it seems to me that you need the dual link DVI cable to get over 1920x1200 (which is a DVI-D).

    Although if that's the case then it doesn't make sense that the same cable works on the 5850.

    EDIT:
    According to http://www.asus.com/Graphics_Cards/AMD_Series/EAH6950_DCII2DI4S2GD5/#specifications

    DVI Output : Yes x 1 (DVI-I),Yes x 1 (DVI-D)
    HDMI Output : Yes x 1 (via DVI to HDMI adaptor x 1 )
    Display Port : Yes x 4 (Regular DP)
    HDCP Support : Yes

    So you need to use the DVI-D output for sure. Check the manual if you're not sure.
  11. Thanks for taking the time to look that up.

    I tried several times switching to the other DVI output. That doesn't change anything (even after rebooting the PC).
  12. I guess the best thing to do right now is contact Asus support.
  13. I believe I may have found a lead:
    http://www.tomshardware.co.uk/forum/332062-15-asus-6950-direct-recognizing-2560x1600-resolution#t2482755

    I will try looking further into that this evening.
  14. http://www.vortez.net/articles_pages/asus_hd6950_2gb_directcu_ii_review,5.html

    I'm nearly certain this is the problem now. Damn it, they could at least mention this switch somewhere...
  15. Wow, yeah that must be it. I've never heard of a card with a DVI switch. I would have assumed it's a BIOS switch.
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