I'm pretty sure it's because your cards don't match.
That would explain why they both do work - no matter which card you put in slot 1, it works, but the other card doesn't. That will be because slot one is obviously the primary slot.
Also, with the Rampage IV Black edition, put your cards in slots 1 & 3. The mapping for the PCI-E lanes accross the slots is as follows:
Snip taken from ASUS website.
If you're only running 2 cards, you can put whatever you want in the empty slots. As you can see, with the graphics cards in slots 1 & 3, they both have 16 PCI-E lanes each (More Bandwidth), so they should be located there.
SLI definitely WON'T work with 2 different cards. they can be from different manufacturers and it usually works, but preferably get 2 from the same manufacturer.
Are you just gaming, or do you do intensive rendering? the Quadro is not a gaming-orientated card, so just curious.
I know some people will SLI 2 GTX 780's for example, and have a lower end card in slot 4 or something - this card is dedicated to PhysX, and that configuration works, but It might be having issues with the Quadro for whatever reason. This is pure speculation, of course - it's just both cards DO work, just not together.
Also, check the switches for the PCI-E lanes located just below the Start and Reset buttons on the Motherboard itself, and make sure you haven't accidentally deactivated any of the slots.
That would explain why they both do work - no matter which card you put in slot 1, it works, but the other card doesn't. That will be because slot one is obviously the primary slot.
Also, with the Rampage IV Black edition, put your cards in slots 1 & 3. The mapping for the PCI-E lanes accross the slots is as follows:
Snip taken from ASUS website.
If you're only running 2 cards, you can put whatever you want in the empty slots. As you can see, with the graphics cards in slots 1 & 3, they both have 16 PCI-E lanes each (More Bandwidth), so they should be located there.
SLI definitely WON'T work with 2 different cards. they can be from different manufacturers and it usually works, but preferably get 2 from the same manufacturer.
Are you just gaming, or do you do intensive rendering? the Quadro is not a gaming-orientated card, so just curious.
I know some people will SLI 2 GTX 780's for example, and have a lower end card in slot 4 or something - this card is dedicated to PhysX, and that configuration works, but It might be having issues with the Quadro for whatever reason. This is pure speculation, of course - it's just both cards DO work, just not together.
Also, check the switches for the PCI-E lanes located just below the Start and Reset buttons on the Motherboard itself, and make sure you haven't accidentally deactivated any of the slots.
Do Quadro and Geforce cards use the same driver? If not, it's likely that the driver for only one is being loaded and that driver cannot operate the other card. I know that's the case with AMD R9 and Firepro cards -- the professional cards use much different drivers and Windows won't try to run both.
Jeff
Jeff
