Thunderbolt 3 external drive slot + M.2/NGFF adapter?
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Thunderbolt 3 external drive slot + M.2/NGFF adapter?  

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New Member
Joined: 1 month ago
Posted by: @joevt

I got the pieces for my first build. 

  1. Thunderbolt to M.2 NVMe enclosure. Other Thunderbolt to M.2 enclosures may have the M.2 connector on the same side as the Thunderbolt port (such as the Samsung X5).
  2. M.2 to PCIe x4 adapter. Different adapters may slightly move the position of the x4 slot or reverse the orientation (only the P4SM2 seems to do the latter).
  3. PCIe X16 right angle riser. Different risers have different heights. The x4 right angle riser is too short.
  4. SATA power cable extension. Straight cable to extend the short floppy to SATA power cable.
  5. Low profile floppy power connector and pins and crimping tool. Replaces the normal sized floppy connector of the floppy to SATA power cable so it can fit under the GPU.
  6. PC Power supply. I suppose anything that can do 12V 200W is sufficient for the selected GPU. A Mean Well 200W power supply is the smallest at 4"x2". Larger 5"x3" variants can go up to 500W and would still be smaller in every dimension than a Flex ATX power supply even if you buy an enclosed variant of the Mean Well. I've never used a Mean Well power supply. I guess you need to make your own AC input cable and DC output cables?

System: Mac mini (2018), 8 GB memory. GPU: Sapphire Radeon Pulse RX 580 8 GB.

I connected the external power supply, turned it on, then connected the Thunderbolt cable, which caused a reboot. It worked after macOS rebooted, and I was able to disconnect and reconnect the GPU. I played some World of Warcraft. Didn't try Windows.

M.2 parts
M.2 parts2
M.2 bottom
M.2 rear
M.2 Connected side
M.2 Connected quarter
M.2 Thunderbolt
M.2 PCIe
M.2 Graphics
M.2 CL!ng


Hi, I know it's quite an old post, but you have the same GPU as I do and I intend to build something similar so I would like to ask you about powering of the PCIe riser via the SATA cable. There is not much info about it on this forum, but I was researching for the past few weeks on different places too and this caught my attention. SATA is rated for 54W, the mini-MOLEX (Berg) is even worse, rated for 36W, however, PCIe can draw up to 75W. Have you encountered any issues with it? Overheating? Stability issues?

I'm not completely sure about the power stuff yet. Can the GPU be powered via the 8pin (which can easily provide enough wattage for this type of card) only? Or does the card REQUIRE those 75W (or whatever) from the PCIe slot? Have you tried to not power the riser at all? Can you try it? Smile

This post was modified 1 month ago

My build will be epic

Noble Member
Joined: 4 years ago

@stepik, I don't think I'll try without a power supply connected to all the connectors because a power supply is required for at least one of the connectors so you might as well use the power supply for all connectors.

I don't think I've ever seen a GPU take 75W from a PCIe slot.

From 3.3V, a PCIe card can use 3A (9.9W)

From 12V a PCIe card has these choices:
An x1 card can use 6W (10W combined with 3.3V).
An x4 card can use 25W (25W combined).
An x1 card can ask for 25W (25 W combined).
An x16 card can ask for 66W (75W combined).

An M.2 slot is not going to allow a GPU to ask for 75W. Anyway, if things don't melt then you're probably ok.



Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case

New Member
Joined: 1 month ago

@joevt, thanks for the info, would be good to start "researching" on the Wiki, I don't know why I overlooked that Smile


My build will be epic

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