Hi Guys,
Mac Store UK has a little blurb on their website that explains two options for internally powering the 1080ti on a cMP.
Quote: " The GTX 1080Ti, Titan X (Pascal) & Titan Xp all require this different setup. The 2 aux power connectors on the logic board will power the 8 pin connector in the mentioned graphics cards. The setup is – 2 x mini 6 pin to 6 pin cables plugged in to a dual 6 pin to 8 pin connector. The 6 pin connector on the graphics card is then powered from a SATA power connector. If you have a spare HDD bay in your Mac the easiest way is to simply plug in a 6 pin to SATA power cable in to your spare SATA HDD socket. If you either don’t have the free HDD bay or would like a neater solution you can draw the 6 pin power from the SATA connector in the second optical bay. This again is straightforward but does take some patience getting the extension cable in the gap between the main compartment and the optical bay." -- Mac Store UK
https://www.macstoreuk.com/faqs/nvidia-gtx-1080ti-titan-x-pascal-titan-xp-power-setup/
[..]
Pulling power from the lower optical bay would be my preference, versus external PSU or sacrificing a hard drive bay.
Question: Anybody here tried this?