Question GPU works only on x16 slot

catalysed

Junior Member
Sep 15, 2021
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Hey guys. I have 2 GPUs. A 3060 and a 1660 super, and they only show up when connected to a x16 slot in the motherboard. When I use a riser, they don't get detected. Other cards work fine with the riser, so it's not a riser issue. I've tried different motherboards, different risers and even different PSU. They have the same issue. I've updated the motherboard bios and the GPU bios. Set the PCIE switch to auto, gen 1, gen 2 and gen 3. None of them work. I have other 3060s and 1660 super which work fine, but just these two cards have this issue.
 

Shmee

Memory and Storage, Graphics Cards
Super Moderator
Sep 13, 2008
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Hmm, curious. Is this for mining, or just in general they won't even be detected at all? If you can, please provide full system specs, such as motherboard, PSU, riser model, etc.
 

catalysed

Junior Member
Sep 15, 2021
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It is for an Ansys simulation rig I use for work.
Tried with 3 motherboards.
AS Rock B450 with Ryzen 5 2600
MSI x399 Gaming Carbon AC with AMD Threadripper 2920x
Biostar B360 with Intel i3 9350KF
I've connected 2x3070ti, 4x3060 and 2x1660s, and they all get detected immediately and work perfectly.
I have 2 PSU and both are connected to the motherboard. One RM1000x, and a Gigabyte P750 GM.
 

Shmee

Memory and Storage, Graphics Cards
Super Moderator
Sep 13, 2008
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This is strange, but I assume that of the 8 cards you have, there may be varying models. Perhaps the specific card models that won't detect when attached to risers simply have some incompatibility with riser use.

Also, are you trying to connect all 8 cards at once, or are you interchanging them for testing?
 

PingSpike

Lifer
Feb 25, 2004
21,668
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I've heard that the newer LHR nvidia cards wouldn't work in slots lower than 8x pcie lanes. They also needed a monitor attached.
 
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catalysed

Junior Member
Sep 15, 2021
9
0
6
This is strange, but I assume that of the 8 cards you have, there may be varying models. Perhaps the specific card models that won't detect when attached to risers simply have some incompatibility with riser use.

Also, are you trying to connect all 8 cards at once, or are you interchanging them for testing?
No change in the variant of the models at all. They are all the same with the same bios for that specific model.
I tried connecting them individually using only that one slot in the entire system, and it posts. When I connect another card in the slot and use these cards in the riser, they don't show up.
 

catalysed

Junior Member
Sep 15, 2021
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0
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I've heard that the newer LHR nvidia cards wouldn't work in slots lower than 8x PCIE lanes. They also needed a monitor attached.
Yeah, that would be for mining specific purposes, you'll need a minimum of x8 with a monitor or an HDMI dummy connected for it to give the full hash rate. But these are not LHR cards. They are the first version of the 3060. And the 1660 super doesn't have any restriction of that sort.
 

VirtualLarry

No Lifer
Aug 25, 2001
53,196
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"Above 4G Decoding" enabled in BIOS? You're going to need that, with so many cards on one mobo. BTW, some mobos max out at 6GPUs, regardless, due to BIOS programming / limitations.
 

catalysed

Junior Member
Sep 15, 2021
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"Above 4G Decoding" enabled in BIOS? You're going to need that, with so many cards on one mobo. BTW, some mobos max out at 6GPUs, regardless, due to BIOS programming / limitations.
4G decoding is enabled. I checked, using only 2 cards on all the motherboards. One for the display and one for the riser.
 

VirtualLarry

No Lifer
Aug 25, 2001
53,196
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Since these are NV cards, check the VBIOS version string using GPU-Z. Are the two "problem" cards, of a different VBIOS revision than the others? If so, contact the vendor for updates.

"I've updated the motherboard bios and the GPU bios. "

I see, this should be covered.
 

catalysed

Junior Member
Sep 15, 2021
9
0
6
Since these are NV cards, check the VBIOS version string using GPU-Z. Are the two "problem" cards, of a different VBIOS revision than the others? If so, contact the vendor for updates.
They're the same bios as all the other cards.
94.06.14.80.18 for the RTX 3060
90.16.48.00.2E for the GTX 1660s
 

Shmee

Memory and Storage, Graphics Cards
Super Moderator
Sep 13, 2008
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Ok, but Larry might be on to something about contacting the vendor for support. There might be a non public BIOS they could give you to try or something, and at least they could give you some support with troubleshooting. Unfortunately I am out of ideas at this point.
 

aigomorla

Cases and Cooling Mod PC Gaming Mod Elite Member
Super Moderator
Sep 28, 2005
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I've heard that the newer LHR nvidia cards wouldn't work in slots lower than 8x pcie lanes. They also needed a monitor attached.
+1
3060 requires a physical 8x slot or it will not work.
It was Nvidia's attempt at anti mining.
 

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