eGPU not recognised without additional power source


First time posting on this forum so forgive me if I have put this in the wrong place.

I purchased:
Mainboard (AMD Ryzen™ 7040 Series) - Ryzen™ 7 7840U
DDR5-5600 - 32GB (2 x 16GB)
and the Cooler Master Mainboard Case

My plan was to basically make my own NUC. It works extremely well! I put the board into standalone mode, dropped in Windows, installed all the drivers, and updated the BIOS etc and I was off to the races. I use an eGPU (Razer Core) with a 3070Ti in it and this tiny little NUC is a BEAST! My only problem is this:

The Razer Core USB C PD port outputs 100W which is the recommended for this board. If I plug the eGPU into any of the 4 ports, I get the power indicator lights on the board and the system will boot but not output video. RDP’ing onto the device shows that all is good except it cannot see the eGPU. If shut it down, disconnect the eGPU, then plug in a separate 100W laptop charger first, get the power indicators, THEN plug in the eGPU into another USB C port and boot it works great! Video output is perfect, full detection of my GPU and amazing performance.

So, it is more of a bugbear than anything else because this takes up 2 of my 4 ports. I don’t think this is a power consumption issue as the GPU will take its power from the PSU inside the Razer Core (the 3070Ti is within spec of the Razer Core PDU) leaving a full 100W to be delivered to the board. Is this something to do with the PCIe boot order or something?


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This might be a hardware bug with the Core in that there’s some cycle between the egpu presenting as a Thunderbolt device, the laptop negotiating power delivery, and the egpu being told to kick the PSU into gear (with a SENSE pin etc). I use an ADT-link board (which doesn’t support reverse PD but I get my laptop power from a Razer dock on the other laptop Thunderbolt controller), and I need two Dell DA-2s to power my 3060Ti but the board can only use its SENSE logic for one, so the other is permanently paperclipped.

If you’ve got some experience with PSUs, maybe you could trip SENSE manually during boot? Take extreme care not to actually short a power pin as that might damage your psu or gpu.


Thank you for the response! I have enough experience with PSUs to know I definitely don’t have enough experience to do that with out killing either my GPU, eGPU enclosure and/or myself.

I wonder if there is a USB C 100W injector or something I could maybe use? Plug the USB C cable from the eGPU into it AND a 100W power line. That way my Framework can receive display/data from the GPU but not use the Razer Core as its power source all while only taking up one port on the board… assuming this injector exists and limits the power put through to 100W and doesn’t put both 100W circuits to the single port.

Something kind of like this: