Dell P31H2: $99

klui

Active Member
Feb 3, 2019
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Sorry to hear that. I was hoping it's some configuration I had to make. I already asked the seller but no response since last night.
 

BeTeP

Well-Known Member
Mar 23, 2019
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I did not buy from this seller. I paid $75 for GY1TD (same card with a low profile bracket) back in 2019. I shared my experience already:
GY1TD uses PEX8734 (32-Lane, 8-Port PCI Express Gen 3 (8 GT/s) Switch).
The pinout is not compatible with cheap SFF-8643 to SFF-8639 cables used with M.2 adapters. So you will have to use the whole Dell kit again. Which increases the cost even further. Which makes it not that interesting to me at the moment. Unless someone can figure the switch config to remap the lanes to make it compatible with the cheap cables.
I bought 3 SFF-8643 to SFF-8639 cables from different vendors and none of them worked with the card. The same cables worked with a cheap M.2 to SFF-8643 adapter. I ended up buying Dell cables and backplane for the GY1TD.
 
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klui

Active Member
Feb 3, 2019
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Ouch, didn't realize they're so limiting. No wonder these cards were so inexpensive. Can't find the backplane except in a complete bundle.

Say @fohdeesha do you have any experience with these 0P31H2/GY1TD PCIe NVMe extenders? It looks like there are throughholes for an i2c/serial interface for debugging. I wonder if those jumpers do something to change its header pin assignments. There is also another pair unpopulated surface-mounted jumper pads above the throughholes. But the jumper block seen on the web are a solid one that hides all 4 posts and I don't want to damage the card/system if they're not bridged properly.
 

UhClem

Active Member
Jun 26, 2012
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NH, USA
The moral, when buying "stuff" with obscure Dell, HPE, etc part #s:
"Expect the unexpected." [Boy Scouts (motto:"Be prepared."), meet up with Murphy.]

I suspect that Dell has connected [for each (of 4) target device] (via PCB traces) the (4) PCIe lanes from the switch chip to the SFF-8643 receptacle in a manner that deviates from the SFF-9402 spec. SFF-9402 defines the (PCIe-specific) pin assignments (lanes and CLK) for both SFF-8643 and SFF-8639 (U.2). "Normal" cables should, and usually do, follow that spec.