BIOS doen't recognize second GPU!

[king_richi]

Hi there,

first of all ... if such a discussion already exists, I'm sorry I searched the web far and wide and didn't find a solution. Another apology if I should have posted this in another category, I'm brand new in the Forum.

My rig is as follows:

Asus Z170 Pro Gaming
2* Geforce GTX 1070
Intel i7-6700k
32 GB DDR4 Kingston HyperX Fury
PSU: Frankfurter 830W
Windows 7 64 bit

My goal was to run both GPU's in SLI mode together but no matter what I do the second GPU doesn't show up in the Windows device Manager or in the BIOS. Both are running perfectly fine when inserted in the first PCI Slot but they are'nt recognized in the second even if I plug in only one GPU. I also tried out the third PCI Slot (though only with a smaller Geforce 460) and this worked, both the GTX 1070 from the first Slot and the 460 from the third worked.
Again plugging the 460 in the second Slot didn't work.
My questoin now is wheather the second Slot is defect or did I miss something in the BIOS?
The BIOS always tells me that the first GPU is running with x16 ... do I have to manually redirect this to x8-x8 ?

Another Problem is, that this PC is at work and I'm not an admin ... so I'm not allowed to reinstall the Drivers (this totally sucks :mad: ) even though I' ve read that this could help. Additionally it took our IT departement an insane amount of time to get this PC into our companies security. Therefore neither flashing the BIOS nor a new Motherboard are an Option.

So any kind of help would be hugely appreciated. This Situation makes me look like an idiot at work ^^

[Nate152]

Hi king_richi

If you've connected the 8-pin pcie power cable and the gpu is not showing up in the bios, it sounds like the 2nd pcie x16 slot is faulty.

[davemon50]

Check to ensure you've disabled the CPU graphics in the BIOS under Primary Display.

It's also possible that you might be "victim" of Windows power management. In the BIOS you can disallow Windows to do that by disabling PCIe native power management. Worth looking at to see if it's causing a conflict. I am on W10 but power management is the source of lots of questionable behavior, it seems.

Do you have enough lanes available to run it? (Do you have an M.2 sharing lanes?) Your manual says you need to run two cards in PCIe 3.0x16 slot 1 (gray) and PCIe 3.0x16 slot 2, and each of them using 8 lanes.

Make sure you have the PCIe generation selected correctly in BIOS, try flipping between Auto and Gen3.

You can disable a PCIe slot on my board (RVE10) with a switch on the board. I don't see that option for your board, but if you have one make sure it's enabled.

[king_richi]

Thanks for the really quick answer ... I will try your suggestions when I get back to working on the PC on Monday.

What do you mean with wheather I have enough lanes avilable? Yes I have an M.2 installed, can this be a problem?
And I also haven't found a possibility to disable a PCIe slot directly on the board.

[Nate152]

davemon50 is referring to dip switches that can switch each pcie slot on or off which your board doesn't have.

The M.2 slots and third pcie x16_x4 slot run off the pch/chipset, having an M.2 SSD installed does not affect the 1st and 2nd pcie x16 slots as they run off the cpu.

With what you've tried, the evidence points to the 2nd pcie x16 slot being faulty.

[davemon50]

You might have the ability to disable a slot in the BIOS. (Don't since you need them 🙂 )

If your M.2 SSD is a SATA drive then it won't matter, but if it's PCIe then it will share lanes (4) with the rest of the system, that's why I asked. For you, with two cards you have to run them as 8 lanes, so check that in BIOS. If you want to read up on lanes, there's many websites to go to for learning, too much to explain here. Just know that total number of lanes are limited based on CPU, chipset and motherboard combination.


EDIT: But.....I see I've crossposted with Nate. 🙂

[Mack023]

I have solved my issue by checking if nvidia graphics card is enabled or not.