MP 1,1-5,1 cMP 5,1 Monterey, USB3

[UKenGB]

Been running this Mac Pro on Monterey for some years now, with a USB3 PCIe expansion card that works. However, one port seems to not like USB3 devices. Not been a big problem, but decided to replace with a newer USB3 PCIe card that also has some USB-C ports and advertised as working in MacOS. It doesn't.

With that newer USB3 PCIe card installed, MP just won't boot. Powers on, but no further. Remove the card and it boots right up. Re-fit the earlier USB3 PCIe card and again it boots perfectly as it always has. Back to new card, but no boot. This is 100% repeatable.

Is it possible anything can be gained by resetting NVRAM and/or power control system (I forget the name, but need to disconnect from power for a few seconds). I can find the exact procedure, but is either reset going to have any effect on whether the Mac Pro can boot with a particular card installed?

 

[reader50]

SMC reset (System Management Controller). On a cMP, unplug for at least 10 seconds. Plug back in, wait at least 10 seconds before pressing the Power button.

It's worth a shot. Could you post the exact USB card models you're using, so we know which works, and which one is hanging a cMP from booting? It helps the next person to avoid the same mistake.

 

[joevt]

Check this thread (at least the first post):
https://forums.macrumors.com/threads/usb-3-x-pcie-cards-for-classic-mac-pro.1501482/