My apologies on posting so much, but does anyone have experience using a m.2 -> PCIe 4x adapter coupled with a a riser cable to add a second expansion card without using bifurcation?
I was thinking of getting one of these
m.2 to PCIe slots and using a
riser cable to connect attach another PCIe device (
USB HUB) to the 3rd slot w/ my 2 slot GPU. This should work just fine in practice, but I was wondering if anyone has come across any weird quirks when doing something like this?
No worries, sorry I didn't reply earlier. I am currently working with an S402 customer who is doing just what you described. There is a problem with the PCIe risers and interference in some of the slots. For example, if we number the PCIe slots from the rear (MB mount) of the chassis up toward the vented panel, we would number them 1, 2, 3, respectively. Now, if you have to use slot #1 (nearest MB mount surface), there are no existing solutions for mounting a PCIe riser in slot #2. For slots #2 and #3, there are alternative riser orientations available that will allow them to work. You can even install in slots #1 and #3 without issue, but #1 and #2 present interference.
My solution that I'm attempting now is to use an AmeriRack PCIe 3.0 bifurcation (x8/x8) adapter mounted to the stock S402 mounts, then extending it using a "straight" PCIe riser cable from the rear of the AmeriRack bifurcation adapter into the mainboard. This solves the physical compatibility but the AmeriRack PCB needs to be modified to mount in the S402 (front holes need to be drilled and rear holes need to be opened up). I haven't yet had an opportunity to test this configuration but I hope to do so in the coming days (after I can get the remaining S402 units listed). One problem is that my drill stripped some of the wire insulation on the AmeriRack adapter when I drilled the front holes and I'm hoping I didn't nick the actual wires.
If this solution works, you'd need to purchase the AmeriRack adapter (
ARC1-PELY423-CxV3) and a straight PCIe Gen 3.0 x16 riser cable. The higher-quality riser cables would work best I'm guessing because of the daisy-chain solution.
Unfortunately, I can't seem to find the AmeriRack adapter for sale anywhere. Looks like we'll need to source another option for bifurcation...