The GPU isn't compatible with the top x16 slot.
The GPU isn't compatible with the top x16 slot.
The HD Cinema 30 inch was dual-link, originally paired with Mac Pro models that included dual-link cards. The DVI-D to Mini DisplayPort adapter works as a passive connection—no USB needed.
I also found via GPUZ that the second slot is locked at x4 bandwidth. I checked the BIOS but didn’t see an option to adjust speeds for the second slot—only the last slot has settings to set it to x4 or x2. It’s unclear how to resolve this issue. My goal is just for the GPU to operate in the top slot.