PCI-Ex1 Card Not Seen when GPU Present

[Brainonska511]

My younger brother recently built a computer with an Asrock H170M Pro4S, Skylake i5, and a Nvidia GTX 980 TI. There are 4 PCI-E slots on the board:
1) Physical and real x16 slot, populated by the GPU
2) 2x physical and real x1 slots, 1 is blocked by the GPU
3) 1x physical x16 slot, but is really an x4 slot.

He wants to use a PCI-Ex1 wireless card, but he's been having some problems getting the computer to recognize it. It only seems to work when the GPU slot is not populated. And he claims to have tried the wireless in both the available PCI-Ex1 and PCI-Ex4 and it isn't seen at all.

I've tried to help him as best as I could, but I'm at a loss for what's up - I've never seen anything like this and I don't personally have access to the machine since he lives a few states away. Any idea what he could try to resolve this problem?

 

[Termie]

Does he have a PCIe SSD in the M.2 slot?

 

[Brainonska511]

Does he have a PCIe SSD in the M.2 slot?

No. For storage, he's only got stuff hooked through SATA ports (1x HDD, 1x SSD, 1x optical drive) and the M.2 slot is unpopulated.

 

[dave_the_nerd]

That's not uncommon - populating certain slots will usually either disable or change the number of lanes available to other slots. The exact implementation can vary from board to board.

Double-check the PCI-E slot configuration section in the manual. It will probably tell you that populating PCI Slot 1 disables Slot 2 or something. There's also probably a way to, say, limit the GPU slot to x8 so that the other slots can be populated.

 

[Brainonska511]

That's not uncommon - populating certain slots will usually either disable or change the number of lanes available to other slots. The exact implementation can vary from board to board.

Double-check the PCI-E slot configuration section in the manual. It will probably tell you that populating PCI Slot 1 disables Slot 2 or something. There's also probably a way to, say, limit the GPU slot to x8 so that the other slots can be populated.

I've thought about that and I didn't see anything like that mentioned in the manual. It does have a bit about Crossfire, where you can populate the x16 slot and the x4 slot and it will run as x16 and x4, but nothing about having to change anything in the BIOS to enable this and it made me think that you could have x16 + a few extra lanes. But I'll suggest the x8 option to him. From looking around, it shouldn't really impact GPU performance.

 

[Termie]

You said the wireless card only worked when the GPU slot was not populated. Which slot was the wireless card in at this point?

 

[Brainonska511]

You said the wireless card only worked when the GPU slot was not populated. Which slot was the wireless card in at this point?

I think he tried it in both PCI-E x1 slots and the x4 slot. I know it worked when it was in both the x1 slots when the GPU was absent.

 

[Termie]

While motherboards sometimes do switch the allocation of lanes between slots, I don't think that's what's happening here. A PCIe x1 slot would never be turned off when a video card is inserted, as that number of lanes wouldn't have any impact on video card performance.

If he's tried again to insert the wireless card in the unblocked x1 slot while the video card is inserted, and it doesn't work, I'd say this is a defective motherboard.

 

[dave_the_nerd]

I've thought about that and I didn't see anything like that mentioned in the manual. It does have a bit about Crossfire, where you can populate the x16 slot and the x4 slot and it will run as x16 and x4, but nothing about having to change anything in the BIOS to enable this and it made me think that you could have x16 + a few extra lanes. But I'll suggest the x8 option to him. From looking around, it shouldn't really impact GPU performance.

You're right, I don't see anything either. (For the curious.)

Termie's probably right. RMA-time.

 

[LTC8K6]

BIOS updated?

One of the BIOS notes mentions an improvement to PCI-E.

 

[Brainonska511]

BIOS updated?

One of the BIOS notes mentions an improvement to PCI-E.

I think he already has 1.8

 

[vailr]

There may be a difference between Skylake i5 CPU vs. i7 CPU, and how some features are enabled with i7 vs. disabled with i5.
Or maybe it's: enabled with Z170 vs. disabled with H170 chipset?
For better all-around board quality, the key feature to look for is ALC1150 audio.
The cheapest mATX Skylake chipset boards (on newegg.com) with ALC1150 audio:
ASRock Z170M Extreme4 LGA 1151
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157675
SUPERMICRO SuperO MBD-C7H170-M-O
http://www.newegg.com/Product/Product.aspx?Item=N82E16813182979
GIGABYTE G1 Gaming GA-Z170MX-Gaming 5
http://www.newegg.com/Product/Product.aspx?Item=9SIA1N83UT3534
The Gigabyte board is what I'm now using, and works fine with both a GPU card and a PCIe x1 LAN card installed.
Of course, I can't say for sure whether replacing the Asrock H170M Pro4S with one of these 3 boards would solve the problem, or not.

 

[Brainonska511]

Just to follow up, he RMA'd the board to Asrock. They sent him a new one. The good news is, the new board fixed an issue he had with the front panel audio header (the original board, it didn't work). The bad news is, he still has this issue where the PCIex1 and x4 slots work when the GPU is not present, but as soon as the GPU is added, they stop working.

I've told him he should try to change the PCIE link-speed setting to see if that helps, but I don't think he's tried that yet. I guess another option he could try would be to RMA the power supply? Maybe something funny going on there? Or, worst case scenario, I may suggest to him to just buy a long CAT6 cable to hook directly into the router and avoid this lingering issue altogether.

 

[VirtualLarry]

Honestly? Sounds like a BIOS bug. Rare, but they happen. Has he tried any different PCI-E x1 cards, in those slots, with and without GPU present?

The x16 primary GPU slot should have its PCI-E lanes fed by the CPU, whereas the multiple x1 slots, or the x4 slot, and the M.2 slot, are probably provided by the PCH.

Since this isn't a Z170 board, I assume that the multiple x1, the x4, and the M.2 PCI-E connections, are all mutually exclusive.

But the CPU and PCH lanes shouldn't ever be mutually exclusive.

 

[Brainonska511]

Honestly? Sounds like a BIOS bug. Rare, but they happen. Has he tried any different PCI-E x1 cards, in those slots, with and without GPU present?

The x16 primary GPU slot should have its PCI-E lanes fed by the CPU, whereas the multiple x1 slots, or the x4 slot, and the M.2 slot, are probably provided by the PCH.

Since this isn't a Z170 board, I assume that the multiple x1, the x4, and the M.2 PCI-E connections, are all mutually exclusive.

But the CPU and PCH lanes shouldn't ever be mutually exclusive.

He has tried two different PCIE wireless cards and sees the same effect.

 

[VirtualLarry]

Sure this isn't an OS/driver issue? It's not like the BIOS/UEFI recognizes or uses Wifi cards.

Edit: Also, what about PCI-E slot power issues? Maybe the GPU is drawing too much PCI-E slot power, and there's not enough for the x1 card.

Are these low-end Wifi cards, or are they high-powered AC cards or something like that?

 

[Brainonska511]

Sure this isn't an OS/driver issue? It's not like the BIOS/UEFI recognizes or uses Wifi cards.

Edit: Also, what about PCI-E slot power issues? Maybe the GPU is drawing too much PCI-E slot power, and there's not enough for the x1 card.

Are these low-end Wifi cards, or are they high-powered AC cards or something like that?

They're just dual-band A/B/G/N cards, like basic Rosewill or TP-Link cards. I don't think it's an OS/driver issue, since they work without the GPU present. Windows detects no trace of the card once the GPU is installed (no hidden devices or unrecognized things in the device manager).

I can't say about the slot power. But shouldn't this not really be a problem since higher end GPUs just draw their extra power from the secondary connections to the PSU?
What I should probably do is send him my old HD5770 just to see if using a different GPU alters the situation in any way.

 

[VirtualLarry]

But shouldn't this not really be a problem since higher end GPUs just draw their extra power from the secondary connections to the PSU?

No, they draw from the slot, AND the PCI-E 6/8-pin supplemental power connection.

 

[Brainonska511]

No, they draw from the slot, AND the PCI-E 6/8-pin supplemental power connection.

I guess I meant I thought they draw a fixed amount of power from the slot, then pull the rest from the supplemental connection, such that other cards would still get the necessary slot power.