Can't enable SLI

warhammer23

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So I have a very wierd problem.
I searched all over the internet and nothing seems to work.

I can't enable SLI on my system and the option doesn't even appear in the nvidia control panel !

-I3 6100
-MSI Z170a Gaming Pro Carbon - bios v1.80
-1x 8gb ddr4 2666 crucial tactical tracers
-1x Samsung 840 pro 128 gb
-2x WD 160 gb 7200 rpm hdd 3.5"
-Corsair TX650W V2
-2x 8800gtx ( evga & asus)
-Win 10 x64 pro latest update and build
-Single monitor 24" fhd via a dvi plug put in the first gpu.

I am testing some stuff but this never happened to me before with the SLI issue.

What i tried so far:
-The psu only has 2x native pci-e 6+2 connectors. I used for the second gpu cable extensions and made sure I put them on separate sata/molex cables from the psu. Both extensions are from 2x 4 pin molex to 6 pin pci-e.

- The mobo has 3 pci-e slots. Tried in every slot and every combination and every time they are shown in the device manager. But nothing to have sli.

- latest drivers for 8800gtx 342.01 tried even older ones. Nothing

- tried 3 different sli bridges and in both sli conectors on the gpus. Extra cleaned the conectors. Nothing

- Got a third 8800gtx (dell) and paired with the others one at a time. Nothing

-Gpu drivers fresh uninstall via DDU and reinstalled. Nothing

So any help is highly apreciated.

Thank you.
 
So device manager recognizes both GPUs. Are both GPUs recognized in Nvidia's control panel or just one? Anyway I hope you are only going to be running very old games because those GPUs due to the low amount of VRAM by today's standards. Today's games require a minimum of 2GB VRAM to run even at reduced quality settings.
 

warhammer23

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Yes, like I said just some tests. I know, most games need dx11. These cards are dx10.

Regarding the nvidia control panel, yes both appear there.
 
The only thing I can think of is that they just won't SLI together in some applications. In the past different makes of the same Nvidia GPU have had SLI issues - even among the *same* video card brand. I had the latter happen with two different EVGA model GTX 970s. I contacted EVGA support and they directed me to their website saying which of their 970 models SLI'd together. My two were not supported due to one of them, the newer one, having a different power phase design (or something like that). The older 970 was a blower SC model, and the newer 970 was the latest model (and last 970 EVGA model they made), the SSC ACX 2.0+ dual fan. So I wound up selling the SC and buying another SSC and never had an SLI problem since.

It was the same thing as you. I could see both in the Nvidia control panel, and could get them to SLI in the control panel and use them at the desktop level before losing SLI capability during gaming. When I exited the game and brought up the Nvidia control panel again, the SLI option was grayed out. A reboot repeated the same thing: works before the game, then doesn't work in game and disables.

Now whether your issue is a compatibility issue or not is anyone's guess. You can try getting help on Nvidia's or EVGA's support forums (or ASUS's) but being such old GPUs I'm not sure what kind, if any, answers you'll get. Maybe someone here will respond with more info, but all I can do is detail my own experience. Good luck!
 

warhammer23

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Wow. Thanks. Will try to find a way to sli 2 identical gpus to eliminate at least if it is a win10 problem or any other hardware.



 

warhammer23

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Ok. Got a set of identical 9800GTs from xfx. Still no luck. Can't believe this ...
Also I have on the way another DELL 8800gtx so i can pair it with the other dell that i have.
If that doesn't work - that's it.

Thanks everybody for the help so far.

 

warhammer23

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Ok. I think i need an exorcist.
Got the identical 8800gtx del - same bios version same everything.
Doesn't work - so after all of that still no answer.

Should I plug both sli ports with 2 sli bridges ?
 


No. That second SLI connector is for three or four way SLI connections. Use the connectors closest to the front of the GPU to the left. You can try connecting dual connectors since your GPUs are so old so who knows. You certainly won't kill anything but I don't think that's the issue. I just think these two GPUs don't SLI. It could be something as simple as different makes of GDDR memory they used between production cycles among the same models. It happens with PC DRAM as well that is not bought in kit form.
 

warhammer23

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That's the thing - I tried with besides the 4x 8800gtxs (2x dell, 1x evga, 1x asus) as well as 2 identical 9800 xfx gt. I mean 2 identical pairs of gpus and still no go.

Plus while back i know for sure that the sli on 8800gtx works on win10 and with the same drivers when i had a 3930k and an asus rampage formula x79 - it's on you tube as well. Then it even worked with gtx 295 in quad sli from different vendors.

And now all of a sudden sli is a mystery.
 
Dude I have no idea. I ran GTX 280s in SLI in a Vista C2D rig circa 2009-2011 or so before upgrading to a Sandy Bridge build with a GTX 480 in 2011.

As a last ditch resort I'd wipe out the entire drive and re-install Windows from scratch (or just buy a new 250GB SSD for cheap and load the OS on that and see what happens).
 

warhammer23

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Yup. I did that 2 times. Once on a hdd and then exactly like you said, i got myself a Samsung 840 Pro 128 GB and put the windows there. Still nothing. All updates and stuff. Even tried with an older variant of windows 10.

Ah and get this, just now i tried to put windows 7 x64 on it - guess what, with skylake cpus and upwards, they are not compatible with windows 7 or 8 anymore ! :)))

So yeah, apparently without human sacrifice I can't make this thing work.
This is for my tube channel - guess I will make a video of what I tried and still nothing.
 

warhammer23

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Guess what guys, no sli works on the new tech regardless of the tech combination. Got myself an older system composed of an 750i xfx mobo and a qx6700 and everything works perfectly ! Even quad sli works since i have 2x 9800gx2s. very very weird !