MP 1,1-5,1 Restore or reinstall Mojave on Mac Pro 5.1?

[Boomish69]

I decided to test some performance differences between High Sierra and my new Mojave install and booted into my High Sierra backup, unfortunately after this it no longer boots to Mojave, it just goes to a black screen! I tried a PRAM reset but same, If I try and repair the Mojave drive via disk utility in High Sierra it shows a lot of errors, safe mode is the same boot problem. So I thought a reinstall of OSX or a Time Machine recovery, but how do I do that as to get to the recovery boot up I have to use my old GPU, and that won’t install Mojave.
Is it a case of wiping my Mojave drive, installing High Sierra then booting with my Mojave compatible GPU , upgrading to Mojave then restoring with Time machine? Seems to me running Mojave on a Mac Pro 5.1 with a GPU with no boot screen holds a few problems when restoring, or am I missing something?

 

[Snow Tiger]

I decided to test some performance differences between High Sierra and my new Mojave install and booted into my High Sierra backup, unfortunately after this it no longer boots to Mojave, it just goes to a black screen! I tried a PRAM reset but same, If I try and repair the Mojave drive via disk utility in High Sierra it shows a lot of errors, safe mode is the same boot problem. So I thought a reinstall of OSX or a Time Machine recovery, but how do I do that as to get to the recovery boot up I have to use my old GPU, and that won’t install Mojave.
Is it a case of wiping my Mojave drive, installing High Sierra then booting with my Mojave compatible GPU , upgrading to Mojave then restoring with Time machine? Seems to me running Mojave on a Mac Pro 5.1 with a GPU with no boot screen holds a few problems when restoring, or am I missing something?

your old non-metal EFI GPU might not install Mojave , but that doesn't mean it won't run Mojave . An EFI GT120 in a cMP will run Mojave , inefficiently though . You'll get a boot screen , progress bars for updates , etc .

An EFI AMD 7950 should do everything , although there are still reports of grey / black screens during certain firmware and OS upgrades .

By the way , if your cMP has Mojave on it you can remove the metal card and replace it with an EFI GT120 to install Catalina with dosdude's installer . Then remove the GT120 , reinstall the metal graphics card and run Catalina nicely .

 

[Boomish69]

your old non-metal EFI GPU might not install Mojave , but that doesn't mean it won't run Mojave . An EFI GT120 in a cMP will run Mojave , inefficiently though . You'll get a boot screen , progress bars for updates , etc .

An EFI AMD 7950 should do everything , although there are still reports of grey / black screens during certain firmware and OS upgrades .

By the way , if your cMP has Mojave on it you can remove the metal card and replace it with an EFI GT120 to install Catalina with dosdude's installer . Then remove the GT120 , reinstall the metal graphics card and run Catalina nicely .

Genius idea thanks Snow Tiger, I’ll get a cheap efi card and I can carry on using the Mac Pro same way as before ..