Cannot get 3rd card to enable in 3x 7950 Crossfire

faxon

Platinum Member
May 23, 2008
2,109
1
81
It's the rig in my signature. I just got a 3rd 7950 today and am learning how to configure and enable 3 way crossfire properly since apparently it's somehow different from 2 way crossfire or im doing something wrong? In catalyst control center the main card shows as enabled, with the second one being linked. the 3rd one however, is showing as disabled. All 3 cards should work fine, and the one thats in slot 3 is actually one of the original 2 (new one has different cooler and needs a slot's gap for air a bit more so i put it on top). Both crossfire bridges are brand new and i tried swapping them around and re-seating them but it just doesn't wanna let me have my triple crossfire. Anything i should be checking for or doing differently to set up 3x crossfire than in a 2x setup? the cards are all running fine right now in milkyway@home absolutely destroying work units like they're someone's bitch, but it's only letting me at the two enabled cards for games, and also in overdrive it wont let me look at the settings on the 3rd one or tweak them because it only shows the two working cards in drop down.

obligatory: yes i put the crossfire bridges on linking card 1 to 2 and 2 to 3, yes all the cards have power (they are all running milkyway@home just fine), and yes i tried rebooting and reseating the crossfire bridges several times now but no dice
 

faxon

Platinum Member
May 23, 2008
2,109
1
81
Okay, so, reinstalled drivers last night, lead to nothing but BSODs on actually installing the drivers. now, i know one of my 5870s from the first 2 is going bad (vram issue) but i thought i'd isolated it to the 3rd which i hadn't, and having been up forever and in a haze i just gave up and went to bed. woke up, swapped 5870s around till i got it to install with the new card and one of the old ones in the rig, rebooted with all 3 in in a crossfire config with the offending card on tertiary duty, upon reboot system twerks it when it sees 3 cards, crossfire enabled across all 3, but no 3D or compute, reboot again and everything is in working order. I should really RMA that damn card now that i have 2 to still run my 2560x1440 monitor while the 3rd is gone.
 

Elfear

Diamond Member
May 30, 2004
7,163
819
126
Try pulling the third card, reboot, express uninstall all AMD software through Add and Remove Programs, shutdown, add the third card with all the Crossfire bridges, and then reboot and install CCC and the drivers.

I ran 3 and 4 card configurations before (7970s) and sometimes it takes a little finagling to make it work. If you open the Crossfire tab in CCC and don't see the drop-down menu to enable three cards, it's some kind of driver issue.

Also do you have the .NET framework installed?