SLi Issues - Not detecting second card

[Jayy]

This is going to be a long post, in before TL:DR.

I have an SLi setup which has been running fine for the first year or so (forget how long I've had them), then I stopped gaming completely. My bro asked if I could put one of the cards in my second rig so he could use it, I agreed. The other rig had the 2nd card in it for some 6 months before I took it back. Since putting it back, I noticed the SLi wasn't working, so I began going about trying to locate the issue.

My Setup

ASUS Sabertooth Z77 Board
i7 3770k Ivybridge CPU (Stock)
Corsair H60 water cooler
16GB Corsair 1600mhz DDR3 Vengeance memory (Currently split 8gb in this machine and 8 in the other)
Gigabyte GTX 680 4GB cards x 2
1000w Coolermaster Silent Pro PSU
Win 8.1 64x OS
Intel 520 SSD's in RAID 0 for OS

That's the important stuff for the purpose of this thread.

The Problem

It seems that the second card in PCI slot 2 isn't being detected at all. Not in device manager (usually shows up twice for SLI), not in the BIOS (Shows "Not detected") and not in Nvidia control panel.

What I've tried:-

Flashing the mobo from 1 behind the latest BIOS to the latest just now.
Brand new SLi bridge to replace the old one (doesn't matter anyway, doesn't detect the card in PCI slot).
Having the SLi bridge on every possible way, including both sets of SLi ports.
Swapping the cards around in the PCI slots 1 and 2 (When in slot 1, each card works perfectly).
Having singular cards run in Slot 1 (Works fine).
Having singular cards run in Slot 2 (Neither work, black screen, no BIOS, nothing but I hear it boot in to Windows).
Resetting the BIOS to optimised defaults.
Resetting the CMOS to see if the PCI lanes would reset.
Changing the power cables to the cards.
Using the latest Nvidia drivers currently. Tried beta drivers and rolling back several months.
Making sure the PCI config in the BIOS is set to 8x / 8x for Slot 1 and 2, instead of 16x for Slot 1 and all others disabled. ( There is a 3rd PCI but because these cards are so big, it can't fit ).

What I think

If the PCI slot 2 was completely fucked, it wouldn't power the card? The fans spin and everything powers up on the second card, so don't think it's that. I can't see any bent pins in the PCI slots, so don't think it's that. There's no dodgey connectors on the cards and they work in Slot 1 with both cards in and with single card in.

The ONLY thing I'm left with now is the fact that I can't remember if I was on Windows 7 Ultimate 64 when I was fully utilising the SLi setup (which I may have been) or if I had upgraded to Win 8 at the time and now currently on Win 8.1 Read a lot about Win 8 fucking up SLi for people and it could be a possibility, as I have also seen a thread about Lenovo machine and applying a patch for SLi on Win 8.

Don't really want to downgrade to W7 but I think it may be the last ditch attempt to see if that's the issue as I "think" that was the last time I had the SLi setup running fine.

There is a 5 year warranty on these boards but it's 1 month for the RMA process, if you're lucky.

In two minds whether to just upgrade the whole thing, new mobo, cpu, ram.

[Jayy]

Thinking about it, as tempting as it is to just upgrade everything, I might just sell them cards.

The i7 and mobo are fine (aside from the SLi issue) and I don't game that often really anyway. My other rig which has an i7 (First gen) in it, is still going strong and performance wise, nothing wrong with it.

The only thing that's depreciating in value here is the GPU's.

I paid near £500 per card for the 680's a couple years ago. I think they would fetch £400 odd for the pair now? I don't know, the card of the moment seems to be the GTX 980 but a pair of 680s will out perform a single 980.

Hmmm, will have a think about this.

[CaNsA]

You have a mobo with a 5yr warranty but you wont RMA it?

Are you mental?

[Jayy]

I will RMA it but as this is my main rig, I need something as good in the meantime. The other rig would probably hold up for a month but I was just pondering with the idea of upgrading everything and RMA'ing the mobo anyway and either sell it or build a 3rd rig.

[trevoriv]

Don't you have to tell the nvidia software that you're running two cards, I'm sure I had this problem when I put my gtx's in sli.
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[Jayy]

You do have to turn SLi on but it usually has an option that says "Configure SLi and Physics".
https://i.imgur.com/F6wJKSL.png

If it doesn't detect the second card in your system at all, it won't show the SLi options.

If you go to Device manager > Display adapters in Windows, it should also include your card twice but mine shows only one.

The biggest indicator is the BIOS says "Not detected" in PCI Lane 2.

[CaNsA]

Deffo no settings in the bios to enable that specific pci slot?

[Ayrton]

Might be Win 8 causing the problem. I've heard that a lot of people have had issues running 2 cards with it and it's a pretty crap OS anyway.
If i was you i'd sell the 2 cards and get a 290. You would get more than enough to cover it and you wont have to put up with all the issues that come with SLI. You could get lucky like my brother did and find one on ebay for £100

[Jayy]

[CaNsA]

From https://www.tomshardware.co.uk/answers/id-2368451/trouble-running-sli-asus-sabertooth-z77.html

[Jayy]

Saw that on Toms Hardware, tried it and nothing happened.

[CaNsA]

PEBKAC

[CaNsA]

You havent got any MVP stuff going on?

[Ayrton]

[Jayy]

[Jayy]