Graphics Possible PCI-E slot error with SLI...?

Morning all - me again!

Just a quick post as bit pushed for time and hoping someone knows an easy answer to this by home time!

Have a Maximus IV Extreme-Z and two DirectCUII GTX670s that I just cannot get to operate in SLI. I have tried:

GTXa (as I'll call it) in PCI-E slot 1, with both pairs of PCI-E power cables from the PSU and the system displays fine
GTXb in slot 1, also with both pairs of power cables and the system displays fine
So I assume slot 1, both pairs of cables and both cards are fine
Either card in PCI-E slot 3 (second SLI slot as per m/board manual) with nothing in slot 1 = no display
Either card in slot 3 with all other slots disabled using the on-board switches = no display

So I'm thinking either slot 3 is faulty or I haven't enabled something somewhere, possibly in the UEFI. Or maybe a driver needs updating, but I thought I'd done them all.

Any suggestions, you helpful bunch?

 

Any other cards plugged into any other PCI-E slots?

 

No, none at all.

I forgot to also mention that the UEFI is at latest version, Nvidia drivers are latest version and I enabled PCI (as opposed to onboard) graphics in the UEFI.

 

Have you tried a different SLI Bridge Connector, they can be flakey?

 

I haven't yet, but only because I had the cards separately in slot 3 and got no display - should I be expecting one with all other slots empty and the only GPU in no. 3?

Also, the UEFI doesn't register the card in slot 3 when both are installed, nor do Device Manager, Nvidia Control Panel or GeForce Experience console.

 

Okay, have now tried these:

- Windows Update - no updates found
- Disconnecting front panel USB 3 (per something I found on a site called Tabinda, regarding IRQ interrupts on the PCIe lanes...??) - no change
- Updating Realtek PCIe GBE Family controller driver - no controller found, so assume install didn't happen
- Swapping SLI bridge round as well as trying it on the other set of contacts - no change

Getting a little bit ratty now. Not the first time Asus stuff has given me grief.

 

....aaaannnd these:

- Switching to second BIOS chip - just returned error code of 00 on the readout LEDs which, according to the manual, is "Not Used". No POST or display
- Setting SLI/PCIe graphics mode in BIOS - no SLI option that I could see, but switched to PCIe in the PCH menu - no change
- Disabling Renesas USB3 controller in BIOS - no change
- Disabling Lucid Virtu MVP in BIOS - no change, other than removing the onboard GPU in Device Mgr

As far as I can tell, the only option I have left is to try one of the other, non-recommended, PCI slots, which I'll do later.

Does anyone know whether the NF200 chip is causing this and if so, how to get around it?

 

Maybe there is dust in the slot and it's not being recognised properly.

 

I'm getting a little bit fg cross.

Have attempted these now:

- Switched to BIOS 2 and cleared CMOS (not expecting much difference to before) - 00 error again ie. nothing doing
- Used the Q-Reset button (per something else I found online) - system just rebooted with no change
- Disabled Marvell controller in BIOS on a whim as I noticed it was flashing up a message at POST regarding "2x PCIe Lanes" - no change (and I only have the eSATA front panel ports plugged into these anyway)
- Unplugged the additional Molex power connector to the motherboard/PCI lanes - no change
- Cleaned all PCI slots with an air duster and PCIe_3 with acetone (because I couldn't find any ethanol and I wasn't about to waste any booze) - no change

So I'm starting to think this is so far the most well-documented failure on t'interweb and that the only option I have left is to do something else I found, namely uninstall PhysX and just reinstall graphics drivers, when...

...I decided to get over my stubbornness and use the NF200 chip. GPUs in slots 2 and 4 instead of 1 and 3, so using what I assume is x16/x16 via the NF200 chip rather than x8/x8 via the onboard Intel...and it boots and recognises both cards, with the SLI option available in NVCP.

WTF?

So, my questions now are:

- Is it worth worrying about trying to get them to work natively? I've heard about NF200 adding latency but should I really care?
- WHY WON'T THE DARN THINGS WORK AFTER ALL THE ABOVE?
- WTFF?!

I repeated the last one from earlier.

Any thoughts?

 

http://www.tweaktown.com/articles/4...l_x8_x8_p67_performance_analysis/index10.html

Think I'll just take the easy option and stop wasting time on this. Shame, as I can't stand unknown issues...