Two GPU setup suggestions?

(This is a cross-post from LTT Forums – nobody tried to answer there)

Hey all! This is my first post in the Level1 forums, and glad to finally be here. I hope you all can help me.

TL;DR: I need to split my PCIe x16 into 2x x16 in order to install another GPU. Any suggestions for a (preferably PCIe Gen4-compatible) riser/splitter? I’m OK with buying an X570 board if necessary.

Before I ask my question, here is my setup (as it pertains to my question):

OS: Linux
Motherboard: Gigabyte X470 Gaming 7 Wifi
GPU: Geforce 1660 Ti
Case: Phanteks Enthoo Luxe (full tower with plenty of clearance for oddball cards)
1x LSI 9300-8i HBA (requires 8x PCIe 3.0)

Just a little background before I ask my real question: I’ve used LInux as a primary OS for every machine I’ve owned since 2007. That being said, a lot of work has gone into getting things just they way I like them, with many cron tasks and other things that I simply can’t get anything done without. So, I have to effectively schedule time to play certain games around the daily work that happens on my machine. If I switch into Windows to play games I can’t play with Wine/Proton, then I can’t get any real work done in the background. And, building another rig is out of the question at the moment.

At one point in time, before I got my HBA, I had two GPU’s in the machine (the 1660 Ti and a 1050 Ti) and successfully got Windows running in a GPU-accelerated virtual machine using Looking Glass. It was tough to set up, but it was worth it! However, since I got my HBA, I no longer have any place I can sanely put another GPU on my board when I can finally get my hands on one. This leaves in a bit of pickle: I’d like to get virtualization set up again so I can do things like gaming in Windows without having to interrupt my quality of life and daily workflow too much.

For a bit I was pretty convinced that I was going to basically have to upgrade this system to a Threadripper just to get the lanes needed to plug all these cards in. However, I neglected to consider the possibility of splitting ports. I’ve never done anything like this before and I’d like some advice and recommendations if anybody has experience in this area. Effectively, I’d like to split my PCIe x16 slot into 2x PCIe x16 slots. I don’t think this board supports bifurcation, but that might be a non-issue after considering the rest of the equation. The way I figure it, even with an active splitter of some kind, I’d still be effectively halving the bandwidth of each card making them effectively 2x PCIe 8x on my PCIe Gen3 board. That’s probably usable, but obviously not ideal.

If I could get ahold of a PCIe Gen4 board and some kind of PCIe Gen4 splitter, then halving the bus speed for each card effectively brings it to Gen3 speeds which is perfectly fine and what I would consider my ideal solution in this situation. I am completly OK with buying an X570 board if required and I am open to suggestions (I prefer Gigabyte and I need 4x DIMM slots that can run at 3600 Mhz fully populated).

Does anybody know of a PCIe Gen4 1x x16 to 2x x16 splitter that could be used in some way to allow me to install an extra GPU? I’ve tried doing my due diligence here, but I’m pretty unfamiliar with this particular area of hardware and my Google-Fu has failed me spectacularly. If anybody could lead me in the right direction, I would be very grateful!

Note: I did find one card that looks like it may work (Supermicro RSC-G2F-A66-X1), but it’s only Gen3 and I hesitate to even try it if there’s potentially a better solution available.

Not a thing yet pretty sure,

What is connected to this, just rust?

Is your bottom slot in use? or the 2nd M.2?

1 x PCI Express x16 slot, running at x4 (PCIEX4)

  • The PCIEX4 slot becomes unavailable when a device is installed in the M2B_SOCKET connector.
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I am not sure this is possible with a consumer motherboard. I’ve seen daughter-boards on servers where they are able to split PCIe 3 (and 4) into multiple lanes but I haven’t seen something on consumer motherboards.

I’m in a similar situation as you although I chose to install the extra GPU instead of the extra PCI-e expansion slot so now I have 2x GPUs (and blocking all other ports). Given I have a 570 motherboard theoretically I could be splitting the top PCIe x16 Gen 4 slot to 2x PCIe x16 Gen 3 and utilize it for both GPUs but alas consumer cards…

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PCIe splitters are prominently proprietary to producer / mainboard [think servers with those horizontal risers]… Gen4 certainly is too new to entertain as well.

Using multiple GPUs, would normally split up a x16 lane to 2 x8 lanes, for most consumer mainboard platforms [which what most SLi / Crossfire boards did, unless specs explicitly stating PCIe lane count / divving up, via chipset].

Sounds like a bit more PCIe lanes be needed, than what conventional platforms would offer. Read up on mainboard/cpu arrangements, until you spot an appropriate base to work off of.

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