NVIDIA Driver detecting only one card, SLI not working

[ruhtraeel]

Hello,
I have a strange issue where the Nvidia drivers on my computer are only detecting one of my two cards. My machine's specs are as follows:

SUN Ultra 40 M2 Workstation
2 X Opteron 2222 Dual Core, 3.0ghz
16GB ECC DDR2 RAM (Although I get a message at POST saying Bad DIMMs from slot 0 to 3)
2 X Quadro FX 4600 768MB GDDR3 VRAM
2 X 160GB 7200RPM HDD
Windows 10/Ubuntu

I've just installed Nvidia's 341.92 drivers, and I don't get any option to enable SLI. GPU-Z thinks I only have one GPU, and device manager only shows one of the 4600s, the other being a "3D video controller" with a yellow exclamation mark beside it. Attempting to update its drivers manually gives me an error saying that the driver isn't compatible with my current version of Windows.

It is also worth noting that I can only seem to get video output, even in BIOS, if my DVI cable is plugged into the second card's second DVI output (This workstation doesn't have integrated graphics). Plugging in the DVI cable into any of the first (top) card's DVI outputs doesn't get recognized as my monitor says "no input signal", as well as the second card's first DVI output.

What could be going wrong?

Thanks

 

[Shmee]

Does the board support SLI per nvidia? What about the SLI bridge?

 

[ruhtraeel]

Does the board support SLI per nvidia? What about the SLI bridge?

Yes, the Ultra 40 M2 seems to support SLI: https://docs.oracle.com/cd/E19127-01/ultra40m2.ws/819-7577-11/819-7577-11.pdf

5-23 is the section that covers how to enable SLI (by turning it on in the Nvidia control panel, although the option doesn't show up for me)


UPDATE: Removing the SLI bridge turns the card from being a 3D Video Controller to a Display Adapter (VGA compatible), which is a start, as now I am in the process of auto installing drivers for it.

UPDATE2: Removing/replacing the SLI bridge and reinstalling drivers seems to have fixed the issue. Thanks!