Become a MacRumors Supporter for $25/year with no ads, private forums, and more!

MP 1,1-5,1 Mac Pro 3,1 upgrade problem -- help, please!


macrumors newbie
Original poster
Oct 14, 2020
Mac Pro 3,1, with Mojave (dosdude patch) and Windows 10 (bootcamp).
I've already installed a GTX 770.
I want to add reasonably fast connectivity -- such as a USB 3.1 card. I know it must go in the pcie 2.0 x16 slot. I have tried several cards. The current attempt is the Silverstone ECU05 card with external USB-C 3.1 and USB-A, and internal connector for USB 3.0 (routed to front).
Here's the problem: If I install the card (needs SATA power) and boot up in Mac Mojave, the card works great! (500/500 external SSD to USB-C). If I restart in Windows, card still works great. But if I reboot to Mac, after booting to Windows, the card stops working, and wont work in Windows either... I remove card, reinstall, and boot to Mac and card works great! Then restart in Windows, again great! Then Mac, nope. Have to remove and reinstall. Seems like the card stops getting power (drive lights not lighting up when connected). Must remove and reconnect SATA power. But that's just a guess.

Any ideas? Or a suggestion of a USB 3.1/3.2 card that might work consistently under both Windows and MacOS?

Register on MacRumors! This sidebar will go away, and you'll see fewer ads.