Mojave running without Metal Graphic card

Using a MacPro 5,1- So I bought the RX580 Graphic card to install Mojave. Did all the firmware updates with High Sierra and Mojave. Installed a new SSD and installed Mojave on it. Very slow start up times and also can not use the option key to start up from other volumes. Apple logo on start up does not appear.
Black Screen till desktop is seen- a little annoying.
So I decided to take out the RX580 and install the card I had been using which is the ATI Radeon HD 5870. Started up on my regular OS (High Sierra) and decided- what the hell see if I could start up the Mojave OS. Well it did and it’s running fine. So I probably needed the RX580 to install-but I’m leaving the 5870 in. For such a great price I got on Amazon- I’ll just keep it. I didn’t mess around around much with Mojave. The Dynamic desktop works (just eye candy -really). Next time I’ll start up on it I’ll check out all the apps and report back.


The black screen is explained by the lack of Apple boot firmware in the graphics card. It would be good to know how to flash upgraded third-party graphics card with the authentic firmware.

Ok it is running all the apps. No problem with that.
The only problem I see is moving the windows or opening and closing windows are a bit delayed. Sometimes moving a window left or right causes the window to split in sections-but that gets corrected in about 1/2 second. So all in all Mojave runs without the graphic card. But as I said previously you might need it (as I did) for the installation.

Final update:
Don’t do it. Even though I was not on Mojave at the time, the ATI 5870 is kaput.
No video- So I guess it doesn’t work. (Da ya think?) I really only booted up on Mojave 3 times.
I installed my ATI 5770- and all is good.
I did notice some flashing of the video this morning on the video- and the other day.
Question for Tidbits: Even though I am not booted up on Mojave, do you think I should just remove the install?
Thanks in advance.