For 4K monitors, the on-board HDMI port only goes up to 30Hz (HDMI 1.4). For non-4K monitors, higher refresh rates are supported.Just to chime in here, if you do have the frame buffer installed, when I upgraded to Catalina I could not get the HDMI to work at 60hz after the login screen unless I put the machine to sleep and woke it up again, even though the monitor supports 60hz. Switching the monitor to 50hz in OSX system prefs fixed it (I used a second monitor attached to the thunderbolt port to do this).
Oh that's unfortunate. What was it that Sherlock Holmes would say..."When you have eliminated the impossible, whatever remains, however improbable, must be the truth."Just swapped the motherboard and tested. Same issue unfortunately.
At this point it’s so hard to if it’s hardware or software at fault. I guess I could try swapping the CPU but that seems so unlikely.
As far as BiOS settings go, the only tweaks I’ve done outside of the guide are fan settings - which I’m assuming doesn’t matter. Thermals all seem fine.
I suppose I could take it out of the case and see if that’s something.
Or, like others have suggested, roll back to Mojave and get rid of the 5700xt and see what happens, but the fact that the rx 580 does the same thing in Catalina makes me hesistant to try rolling back.
For 4K monitors, the on-board HDMI port only goes up to 30Hz (HDMI 1.4). For non-4K monitors, higher refresh rates are supported.
Yes the OCW 10G Ethernet did work prior to Thunderbolt bus.Good idea -- I'll create a new section entitled Extended List of Compatible Devices with Thunderbolt Bus. It will include devices that began to work after new firmware was flashed.
Did the OWC 10G Ethernet Adapter work without Thunderbolt Bus? I believe the CalDigit TS3 Plus dock has worked before.
eGPUs, Thunderbolt Ethernet Bridge, Target Disk Mode, and perhaps some LaCie storage arrays(?) will be among the entries in the new section.