https://www.jeffgeerling.com/blog/2025/not-all-oculink-egpu-docks-are-created-equal Skip to main content Jeff Geerling Main menu * Merch * About * Blog * Projects Not all OCuLink eGPU docks are created equal September 29, 2025 I recently tried using the Minisforum DEG1 GPU Dock with a Raspberry Pi 500+, using an M.2 to OCuLink adapter, and this chenyang SFF-8611 Cable. After figuring out there's a power button on the DEG1 (which needs to be turned on), and after fiddling around with the switches on the PCB (hidden under the large metal plate on the bottom; TGX to OFF was the most important setting), I was able to get the Raspberry Pi's PCIe bus to at least tell the graphics card installed in the eGPU dock to spin up its fans and initialize. But I wasn't able to get any output from the card (using this Linux kernel patch), and lspci did not show it. (Nor were there any logs showing errors in dmesg). Pi 500+ JMT eGPU Dock Setup I switched back to my JMT eGPU OCuLink dock for the rest of my testing, and uploaded a video detailing some of my struggles, and a blog post detailing the Pi 500+ eGPU testing. A few commenters mentioned they too had issues with the Minisforum DEG1. But a few of them looked closely at the OCuLink cable Minisforum included, and noted there were a couple extra colored wires going through the cable sleeve that didn't seem to be present on other cables--like the chenyang I was using! They suggested I try swapping cables. So I did... and testing it with an RX 6500 XT worked! Minisforum dock working with AMD RX 6500 XT eGPU on Raspberry Pi 500+ Looking closely at the cables side by side, I can confirm what some of the commenters said: the cable that came with the DEG1 looks like it has additional colored wires going between the connectors. OCuLink cable that came with Minisforum DEG1 Moral of the this portion of the story: not all OCuLink cables are created equal. Going Deeper But then I swapped back to my RX 7900 XT, the one that was previously unrecognized in the Miniforum dock... and it still wouldn't work. $ lspci 0002:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 30) 0002:01:00.0 Ethernet controller: Raspberry Pi Ltd RP1 PCIe 2.0 South Bridge I tried all three switches in different settings, I tried swapping OCuLink cables back and forth again... nothing. The RX 6500 XT was happy as can be, but the 7900? Nope. I even popped in an Intel B580 card, and it worked too... $ lspci 0001:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 30) 0001:01:00.0 PCI bridge: Intel Corporation Device e2ff (rev 01) 0001:02:01.0 PCI bridge: Intel Corporation Device e2f0 0001:02:02.0 PCI bridge: Intel Corporation Device e2f1 0001:03:00.0 VGA compatible controller: Intel Corporation Battlemage G21 [Arc B580] 0001:04:00.0 Audio device: Intel Corporation Device e2f7 0002:00:00.0 PCI bridge: Broadcom Inc. and subsidiaries BCM2712 PCIe Bridge (rev 30) 0002:01:00.0 Ethernet controller: Raspberry Pi Ltd RP1 PCIe 2.0 South Bridge So now I'm left scratching my head: what's different about the RX 7900 XT? And why does my cheaper $50 eGPU dock seem to work with everything, but the $99 Minisforum DEG1 doesn't? Searching through forum posts, I even found someone running a 7900 XT in the DEG1 on a Pi, so maybe it's just a strange fluke with my setup? Inconsistencies like these really bother me. And they usually eat up an entire afternoon, because I'm always certain it's a PEBKAC, and I usually exhaust every route debugging before I'd waste a vendor or a maintainer's time with a bug report! OCuLink cable dimensions and pinout from Amphenol I haven't yet torn down one of these cables to try to figure out which pins are perhaps missing on the chenyang cable (see OCuLink Pinouts here. The bigger issue there is, I can't find a source for the cable Minisforum includes separate from the DEG1 dock, and most online listings don't clearly show which kind of cable you'll get--with or without the extra wires! Further reading * Exploring WiFi 7 (at 2 Gbps) on a Raspberry Pi 5 * Full eGPU acceleration on the Pi 500+ with a 15-line patch * External GPUs and the Raspberry Pi Compute Module 4 amd gpu egpu minisforum pcie raspberry pi oculink cable * Add new comment Comments Jeff Geerling - 7 hours ago Interestingly, I put my RX 7600 in the Minisforum DEG1 as well; and it exhibited the exact same symptom: * Fans spin up after Pi initial startup like it's initializing, then they spin down * lspci shows nothing * Tried with every combination of 'Follow Start' and 'TGX' switches toggled on/off * Switching back to the cheaper dock worked flawlessly (with either cable) So now I'm wondering if the 7000-series AMD graphics cards have a different PCIe initialization scheme that doesn't like something on Minisforum's DEG1 dock? I don't have any other 7000-series cards, besides the XFX Merc 310 (7900) and ASRock Challenger (7600). Edit: Got the same issue with an RX 460! Not sure what's going on here--but same exact thing, it didn't work in Minisforum dock, worked fine in cheaper JMT dock. Same power supply, same cables. * Reply Chris - 5 hours ago I also got that same Minisforum dock and hooked it up to a PI 5 with a 7600 XT. I had no issues. Didn't have to open it and change any switches, it worked first try. I am using the cable it came with. Haven't tried the new patch but I plan to soon. I was using it for llms though and did not hook it up to a monitor. * Reply Pete - 4 hours ago That sounds like it might be a voltage drop issue? * Reply Jeff Geerling - 4 hours ago In reply to That sounds like it might be... by Pete I've tested with two power supplies that have been extremely reliable (Lian Li 750W and Corsair RMx 650W), and the same power supply and cabling works fine in the JMT dock (I just move the cables over when I switch docks). So unless the Minisforum has something on it pulling a ton of power when a card ramps up, it doesn't seem like that'd be the case. Stranger things have happened, of course. * Reply Anonymous - 25 min ago thanks * Reply Sam - 5 min ago I wonder if its related to that problem people had with EVGA motherboards where a couple extra SMBUS pins were causing systems to fail to boot * Reply Search [ ] [Search] Geerling Family Crest All content copyright Jeff Geerling. As an Amazon Associate I earn from qualifying purchases. Top of page.