M18X R2 disabling one GPU confuses machine.

Hi all,

I have an M18X R2 here which has two 7970M GPUs onboard. I wanted to check that both are fully functioning, so I disabled one of them, with the result that the machine is only displaying low resolution (it seems to think it has no drivers for the remaining configuration). Should I be worried that the remaining GPU is not working? I was expecting disabling one GPU would just make it use the other one.

Cheers in advance.

 

An update: when I run 3Dmark with crossfire disabled (but both GPUs enabled in the device manager), the benchmark itself says 7970M(1x) with a score of P5671.
When I run 3Dmark with crossfire enabled, the benchmark STILL says 7970M(1x) but now the score is P9487.
When I disable crossfire and disable the bottom GPU (in device manager), the machine still runs HD graphics.
When I disable crossfire and disable the top GPU, the machine blackscreens (not bluescreens - it is still running windows, just not displaying anything on screen).

Can anyone explain this behaviour? Is it impossible for the machine to run graphics from the second GPU alone even though it is identical to the first?

 

@Dangerous_Dave To test a GPU in the R2 it needs to be in the primary slot, as you have discovered all sorts of things happen when you try and isolate the secondary card. The MXM slots are not equal as PCI-E slots are in a desktop (for the most part), so if you only have a card in the secondary slot the computer, the R2 simply wont function. I know its a pain but to test your secondary card you will have to disassemble and physically try it in the primary slot after you swap the heat-sinks off course.

To explain what you're observing: bad hardware detection on FutureMark's part as crossfire is obviously working to get P9487 points. I'm guessing that disabling crossfire and the bottom gpu has just left the first card running as normal, while disabling crossfire and first gpu has effectively disabled both gpus... hence the black screen.

Hope that helps.

 

In M18xR1 first gpu in device manager is SECOND in laptop - PCI Lane 7
Second in device manager is FIRST (primary) in laptop - PCI Lane 1

 

Kenny nailed it, you can't isolate the secondary without physically swapping them over which would also require swapping the heatsinks

 

Thanks to all. I'm reasonably confident they're both working. The Crimson drivers also bumped performance up towards P11000, which I was quite surprised about.