6990M CrossfireX M17x R2 Not Working

Hello NBR M17(x) forums. Long time no see.

Anyway, the reason I'm posting - I upgraded my R2 from two 5870M to 2x 6990M back in 2011. It worked for years and then all of a sudden it seemed I was unable to find the Crossfire option in the driver. CCC and GPU-Z see the two GPUs, but CrossfireX is disabled and there's no toggle. Windows 10 can't be the issue seeing as how the issue started on 8.1, several months after my upgrade from 7. I've tried clean removing the drivers and reinstalling several times, tried reinstalling Windows even once or twice.

I've tried replacing the CFX ribbon cable, no dice. Is it possible the pins on the CFX connectors on the cards have been damaged? I have removed the cards once since the upgrade to replace the thermal paste, but I was always fairly careful when reconnecting the cable.

Any ideas?

 

My bet would be on the cf cable, but since you've replaced that afaik the amd cards also dont want to cf if one of them has problems... I highly doubt that the cf connector can go bad.

 

Likely second card decided to die.

 

6990M is constantly dying, nothing new.

 

Wow, so they're capable of dying and still being visible? That's an interesting behavior. I mean, GPU-Z sees both cards, they both show up in the driver, just not CrossfireX-able.

The only way of getting a definitive answer on that would be to attempt using one card at a time in each slot...or at the very least putting the slave card that obviously isn't in use and plugging it into the master PCI-E slot. Going to have to be a REALLY dead weekend before I up and dedicate that kind of time to this.

Interesting that they're famous for dying. They always ran quite hot, but not dangerously so (generally peaked during long gaming sessions around 75C if I can recall, idled around mid 40s).

 

Yes, cards can still POST and show up in the BIOS and not function. I had a 6970M and 7970M that did this, as well as a GTX 780M. 6970M/6990M had notorious solder issues that held the core to the MXM board. Likely you can reflow with no-clean liquid flux and a heat gun set to 400 degC.

 

6990M/6970M almost always die and is still visible because memory solder had factory defect

 

Okay. Does anyone know if there's a way to tell which card is in which slot on a software level for the R2? I'd prefer to know which is defective before I accidentally extract the functioning GPU.

 

Looking at the m17x r2 as if you are typing on it, the left slot is the primary slot/card.

 

Doesnt matter if you extract the working one or not, the laptop wont post without a card in the primary (left hand) slot.