View Full Version : Crossfire 2x HD6950 DC2

04-30-2012, 06:24 PM
I'm trying to run 2 Asus HD6950 2GB (DC2) in crossfire on a system (specs below). Both video cards are visible under hardware management and in CCC. However, one of the two cards (the one in slot 3) is displayed as disabled.

- mobo: Asus P6X58D-e (3 x PCIe 2.0 x16 (x16-8-8 of x16-16-1))
- 16 GB DDR3 1088 corsair
- 2x SSD (90 en 240 GB) sata3
- Intel i7 core 3GHZ 8mb cache (950 series)
- Corsair 850watt power supply
- 2x Asus HD6950 2GB in PCIe slot 1 and 3.
- windows 7 home edition

At the time I choose the mobo for its excellent crossfire and sli support. After several weeks of testing and researching I still do not get a crossfire enable switch in CCC. Neither MSI afterburner or GPU-Z show additional usage of the second card under heavy duty (e.g. battlefield 3 @ ultra)

What I did so far:
- deleted en reinstalled CCC drivers all the way back version 11.x till 12.4.
- install CCC profiles (till 12.3 cap 1)
- switch cards between both PCIe slots, all possible combinations
- complete reinstall windows 7
- mounted one card at a time
- crossfire bridge(s) in single or double setup (or not at all)
- use native asus drivers (older CCC) via asus.com - cmos reset
- installation of 9.2 intel chipset drivers

All actions were performed in virtually all possible combinations. In some I ended with IRQ issues in other a complete disabled card (also in hardware management). Both cards are functioning properly atm.

Since the cards are three slots wide I utilize slot 1 and 3. I do have a PCIe riser card available to connect the 2nd card to slot 2.

Anyone any ideas? I kinda sucks to spend like 800 euro's on three specific components you expect to function in harmony...

04-30-2012, 07:16 PM
not sure what to tell you

the closest thing i've got is crossfire ASUS 6870 DC2, and they work ok on 12.4, was better on 12.3

only problem i've got are my 2x ASUS 7970 DC2 can't get them to crossfire properly 12.4, only 11.12 (RC11) is stable on that card

some how ATI broke the crossfire drivers with 12.4

although your case sounds like something completely different as it's not even detected properly.

make sure you have enough PCI-E powers going to those plugs on the video card
make sure each card is on a 16x PCI-E slot
what size/power is your PSU?
make sure you are on stock CPU speed
upgrade to the latest MB BIOS
upgrade to the latest GPU BIOS

usually older drivers works better than newer drivers

04-30-2012, 10:22 PM
Thanks for the quick reply!

I might have a go with 11.12 again, some version of CCC worked properly (not sure anymore as its 6 months ago), this might be the one.

Power is OK, as PSU is 850W corsair, should do fine if the cards are not at 100% load.

Sadly the mobo only has room to fit the cards in 1 and 3. I'd have to use a riser to utilize the PCIe x16 slot 2. Slot 3 only has x1 :(

Mobo has latest bios, version 701

I could upgrade the bios of the cards, flashing in the past however did not work out very well for me. Any directions where I can find the latest roms for this type?

If all else fails I guess I'm stuck with getting a better mobo where I can fit both cards normally in 2x PCIe 2.0/3.0 slots x16

05-02-2012, 05:30 PM
Installing 11.12 did not allow me to enable crossfire either, out of options atm

05-03-2012, 09:43 AM
May I suggest that if possible you do a full install of OS. If the cards did work once before in crossfire then they surely will again.

I would test each card first. Just to make sure that each card is 100% - I am sure that they are but I am nuts for making sure that variables are removed when I problem solve.

Then I would test the PSU connectors. Swap them over and see if they work in the other card. Visually inspect them. Run your fingers along the cables to feel for nicks or for abrasion.

Once you have done all that then do your OS install if possible. If not post back and we will try something else.