Are they actually extra? Or does the other cable simply route them over coax? Answer here is to grab a couple SFF-???? Breakout boards, a scope, and a signal generator.

Another thing to consider is isolating all but the first PCIe lane.

In my experience, incompatibilities like that have for the most part been due business partnership decisions. Let me give you an example. A company that designs motherboards may state that one board should be compatible with a full range of other hardware in the market, e.g. RAM, PCIe, M.2, etc. The reality is that they usually partner and/or are locked into certain vendors, contractually, that supply them with their products for the board. You can see this in their products spec pages, in a section titled, "Support List," with a warning that should you deviate from this list, they will not guarantee 100% functionality. Basically, the company tests each product that they list, and if does not work properly, they either tweak the board, its firmware, or communicate this to the third-party vendor to see if they can provide a solution. Most companies that sell these boards or devices more often than not, are small, do not have enough R&D funds, or manpower to do the proper research, testing and adjustments to their products, since devices are already 6 months behind current technology when they are released into the wild. Usually, customers can call into the company's support line and report the problem. The company may or may not address the incompatibility of their board with the third-party product if they see that there is potential for increased sales should the third-party device prove to be a trending product, or the customer is a high-volume order customer. More often than not, the incompatibility is not properly addressed.

Just my thoughts :|

i had a nuc with an eGPU, connected via a simple usb/thunderbolt connection, and I recall it was a nightmare to setup

I understand the focus on the cables, and as an owner of several Minisforum devices, IME they don't really do compatibility very well (e.g. linux on V3). Their specialty seems to be taking reference PCB's, down costing them by changing/removing components, and then putting them in very unique enclosures. They're one vendor I would avoid considering - unless it's x86.

I've actually been dealing with this myself recently, but only the gpu portion. I've been trying to get a gpu working on the orangepi RV2 just to see if I can. The tools for building the kernel for orangepi are kind of bad though.

But no, the 2 old amd gpus I have just don't show up at all in lspci, testing the RTX 2080 and RX 7800 both did show up though.

I can’t seem to find the answer about this, is there anyway to get an oculink through the x4 slot on framework desktop?

I like how the comments section on Jeff Geerling's website now looks exactly like an HN thread. I did a double take, haha!

Why use an egpu with a raspberry pi? all the games are x86 based. LLMs?