Radeon 4850 Crossfire, one GPU not working

Hi tom's hardware, I've discovered that one of my GPUs is not working at all.

Bare with me while i describe the procedures I've tried to resolve this issue without success.
The card IS detected by catalyst center but it shows 0% activity at all times.
I've used all kinds of software like speedfan,gpu-z,furmark and HW to monitor the temperatures of both GPUs and even when I'm running fullscreen fullmark it only shows one GPU.

The temperature of the malfunctioning GPU is never above 45 Celsius, while the working one goes up to 90 with furmark (if I let it run a while).

The other weird thing is that furmark recognizes my second GPU when I turn off the crossfire option(disable) in Catalyst Center.
It doesn't recognize both GPUs with crossfire enabled, how weird is that!

Though even when it recognizes the second GPU, it still shows 0% activity and no change in temperature when running the stresstest.
Also, I get a score of 300 with a 8second fullscreen test with crossfire enabled but with only one GPU recognized by furmark.
I get a score of 160 with a 8 second fullscreen test with crossfire disabled but both GPUs recognized by furmark

Asking my brother who claims to know his stuff around computers he said to me that furmark and catalyst may show 0% activity but the card is still working.

Then my question is, if the card is working, why isn't the temperature of the suspicious card rising?

Another thing is that if I switch the "blue end" cable connecting the monitor with the GPU so that it will connect the monitor and the suspicious GPU, the screen stays black, as if it wouldn't recognize the GPU.

One more thing, when I start gpu-z I get a message that OpelCL is not working and I should reinstall the AMD APP SDK thing. Well, I've done that too and still getting that message.

My thoughts on this would be that the OpenCL isn't recognized on the malfunctioning card, cause OpenCL has to be working on one card cause the furmark test is a OpenCL test, isn't it.

Couple of things:
-Yes, I've double checked the cables.
-Yes, I've double checked the crossfire bridge
-Yes, I've reinstalled Catalyst Center several times, even going to older versions back and forth.
-Yes, the crossfire option is enabled in Catalyst Center

Ok, I hope I haven't forgotten about anything important. Let me know If more info is needed.

Oh my specs are:

gpu: crossfire 4850 radeon
processor: AMD Phenom II X4 965 Processor (4 GPUs) ~3.4 GHz
motherboard: ASRock M3A770DE
power supply: OCZ600MXSP (600W)
11 answers Last reply Best Answer
More about radeon 4850 crossfire gpu working
  1. Take the good card out. Leave the card that isn't giving a signal where it is. See if the card functions properly by itself first. The card can be bad, or the PCIe slot could also be bad, and you haven't mentioned testing either.
  2. Well I said that I've already tried connecting the cable to the suspicious card and the monitor stays black as night, meaning the card isn't properly recognized?

    As with the GPU slot, I'm gonna test that out first thing in the morning.
  3. Well I assumed you meant you tried it when you had both cards installed. Don't know if you tried to card by itself with the other one removed from the computer. Basically have to find out if that card and that PCIe slot work 100% first.
  4. Ive run test and:

    - Both cards WORK, but only on the upper GPU slot.
    - both cards are recognized on the lower slot but the activity is 0% all the time
  5. Best answer
    There has been talk of a funky new driver that is supposed to be specifically aimed at fixing Crossfire issues, the only thing that you will have to bear in mind is that you might have a hardware issue in which case the driver isn't going to fix anything. Has Crossfire ever worked and if so what driver were you using at the time and have you tried that driver now to see if things start working again?
  6. I've never experienced any major fps issues until I moved on to the higher tier games like cod and such (Maybe 2 weeks ago). That's when I started to monitor the temps and - since not long ago - usage percentage and realized there was an issue.

    1.So if the bottow PCI slot is broken, how come the card is still being recognized by the system but not used?
    2. Second thing, is there a need to buy a new motherboard before buying a new - single - GPU which will be in the working PCI?

    Oh, and yes, I've gone back to old driver versions but that hasn't done anything
  7. I would suggest waiting for the new driver before going out and buying anything.
  8. any ETA on that?
  9. I think it's supposed to be released at the end of this month.
  10. Alright then, I guess there isn't much more to do else then to wait. Thanks
  11. very late respons, sorry for that, I noticed ccc and gpuz show crossfire enabled when only one crossfire connector is used, but then on my system only one gpu does the work when playing fullscreen 3d games, after connecting the second connector both the gpu worked together and as far a i can tell the load is evenly spread over the two gpu's.

    2 x asus Radeon HD 4870 (no OC) on a standard Asus P5E mobo.
    using Atitraytool (and once CCC to enable CF, atitraytool is greyed out to enable CF) and latest (not the beta) drivers
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