PCIe Bifurcation on Minisforum BD795i SE

Hardware
1

Hi, I have a Minisforum BD795i SE Mobo in a 4U full atx server chassis (Lanberg SC01-3504-10B)

This mobo does have only one PCIe x16 5.0 slot and Im looking for best possible solution to split that into either x8x4x4 or x8x8 slots since I want to put intel arc gpu (x8), asm sata controller (x4) and possibly in future sfp+ card (another x4). Problem is, most of bifurcation cards create new slots at 90 degree related to the original slots or use much expensive solution that utilizes MCIO cables.

From what I understand there are really two options here. I could use splitter like this:

But then I would need a bracket adapter that rotates slots in my atx case like this:

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(thin plates between brackets would need to be sawed off with dremel or something)

OR
I could go with ADT Link adapters like this one (much more expensive) Amazon.com: JMT ADT-F36B-F37B-D8S PCI-e 4.0 X16 to X8 X8 MCIO Bifurcation Adapter Riser Card 256G/bps Split Extender SFF-TA-1016 with Power Cable (50cm) : Electronics
And then 3D print mounting plate that would go betweeen daugher boards and chassis.

Im not keen on any of those two solutions, but maybe someone had already did a research on this and could recommend something?

Thanks for help

2

Hi. This forum is mainly for questions involving 45Drives’ products in some way. A better place to ask for general help might be reddit r/homelab or ServeTheHome forums.

One thing you could consider with your first option is instead of plugging the PCIe card directly into the motherboard, to place it next to your motherboard in the case in the PCIe slot area and connect it to your motherboard’s PCIe slot with a cable like this;

You will also need some sort of standoffs, perhaps those are ones similar to the ones used in your case, something you 3D print, adhesive ones, etc. If you get the height right, you should be able to use the existing PCIe slot openings in the back of the case.

Unfortunately, I don’t think anyone manufactures a pre-made PCIe-slot expander like that.

You will also need to consider power. I’m not sure what graphics card you intend to use, but a single PCIe slot can only provide something like 70W, so the two outboard cards together can’t draw more than that from the slot. You may need to connect them directly to the PSU in this setup whereas in a normal setup you would not.

That’s probably still cheaper than your second option, but the jank factor is a lot less with your second option. Of course compared to a new mATX or ATX motherboard, either of those options are still still kind of pricey relatively speaking. Ie, you’re paying 25% of the cost of a new motherboard or more just for this expansion.

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