GPU in second pcie slot is not detected - Gigabyte X570 AORUS PRO

Vijay Gill

Vijay Gill

Vijay Gill

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29 Dec 2019
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7
Hi

I have got this rug running a few weeks ago and now I am trying to add another GPU (MSI RTX 2080 Super Gaming Trio) but the motherboard does not seem to detect the card in the second slot.

I tried everything (moving the existing working card to slot 2 and new card to slot 1 / having only one card in slot 2 etc) but nothing seems to work. I have fiddled with settings in BIOS too (like enable $G decoding etc) but no joy.

Can anyone suggest anything before it is concluded that motherboard has problem and needs to be RMA'ed.

The CPU is AMD Ryzen 5 3400G with RX Vega 11 Graphics. I am using this setup for machine learning and want to use RTX cards purely for ML and use on-board graphics for display purposes. And yes, I tried disabling IGD (on-board graphics) also but that did not help either.

Thanks.
 
Does the graphics card work on it's own?

Does the 3400G actually support a 2nd GPU? I thought the 2nd gen APUs had less lanes. You could try the 3rd slot, from the specification it appears that this is connected to the X570 instead of the CPU, so it might work there.
 
Tetras said:
Does the graphics card work on it's own?

Does the 3400G actually support a 2nd GPU? I thought the 2nd gen APUs had less lanes. You could try the 3rd slot, from the specification it appears that this is connected to the X570 instead of the CPU, so it might work there.
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Silly me! Thanks for pointing out the PCIe lanes stuff! Yes only one 1 slot is supported for 2nd Gen processors. IT's clearly mentioned in the specifications on Gigabyte's site. I will put the second GPU in third slot and report back.

Thanks for your reply.
 
mmm, sort of... but not. It's actually based on Zen+ not Zen2 like the rest of the "proper" 3000 series (eg 3600 and up). It's a stupid naming convention in my opinion!

Also of note is that the 3600 and up are PCIe 4.0 while the 3400G being actually based on the previous gen is PCIe 3.0

I think your Motherboard would be treating it as the previous gen version of Zen+ that it actually is rather than the current gen Zen2 that the name arguably implies.
 
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That's a shame, I was hoping it would work in the 3rd slot. I'm surprised it won't because it is not much different to any PCI-E card, like a sound or network card and I'm pretty sure the lanes are available even with an APU.
 
Zeeflyboy said:
mmm, sort of... but not. It's actually based on Zen+ not Zen2 like the rest of the "proper" 3000 series (eg 3600 and up). It's a stupid naming convention in my opinion!

Also of note is that the 3600 and up are PCIe 4.0 while the 3400G being actually based on the previous gen is PCIe 3.0

I think your Motherboard would be treating it as the previous gen version of Zen+ that it actually is rather than the current gen Zen2 that the name arguably implies.
Click to expand...

There's an option in the BIOS which allows you to change the PCIe configuration to suit Generation 2 or Generation 3. I tried that too (default was Auto) and that did not work either.
 
Threepwood said:
Okay, I can't see where you asked that at all, but, the answer is the same.
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I asked dose it suppoer 8x.. I never asked if it was backwards compatible. Your reply was wrong

Amd supposed CF with 16x 8x and 4x pcie lanes.
But sli only worked with 16x or 8x what I am asking is dose the new gpus support 8x still, the motherboard in question only dose dual gpu at 8x 8x per 16x socket

Also dose the motherboard support sli?
Edit yes sli is supported
 
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From my limited understanding of using them for other purposes (like mining or whatever), it doesn't actually matter if SLI is supported, only that the BIOS can detect the graphics cards in the PCI-E slots (presumably then showing up in device manager in Windows) and allows you to install the drivers sufficiently for it to operate. If the chosen software can make use of it, it is job done.
 
Tetras said:
From my limited understanding of using them for other purposes (like mining or whatever), it doesn't actually matter if SLI is supported, only that the BIOS can detect the graphics cards in the PCI-E slots (presumably then showing up in device manager in Windows) and allows you to install the drivers sufficiently for it to operate. If the chosen software can make use of it, it is job done.
Click to expand...

For sli the drivers need to detect the pcie lane speed of minimum 8x with older cards before you can enable sli. With the newer cards dose it require a full speeds 16x lane to enable sli?
 
I don't know, but the OP is using them for machine learning, so I don't think it matters for why the 2nd card doesn't get recognised.
 
Thanks all for your responses! Sorry for late reply. Life took over everything after I started this thread.
It turned out my CPU is too weak for two GPUs. This was confirmed by message from Gigabyte support itself.
Also putting the GPU in third slot and then using NVLink is not possible because NVLink can be used when GPUs are in slot 1 and 2.
 
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