I can confirm that Mojave installs fine with GT 710 (see updates below regarding card issues)
Last night I replaced my original ATI Radeon HD 5770 with this bargain
MSI GeForce GT 710 I bought from Amazon, and I can confirm that:
- It fits perfectly in my Mac Pro
- It works
- The App Store allows installing Mojave
- The Mojave installation is successful
One caveat is that for some reason, after installing Mojave, before it got to complete the boot, the screen just went black. I waited for 30 minutes, then shut down the computer by simply pressing the power button briefly. When turning the computer back on, the Apple sound did play, but the same behaviour persisted - black screen, and a brief press on the power button powers off the computer. I tried many things, including:
- SMC reset (both the standard way of removing the power cable, and the alternative of pressing the button on the motherboard)
- PRAM reset (not sure if the keyboard key combination does anything when performed on an external keyboard though)
- Connecting the screen with HDMI instead of DVI (even though the graphics card initially worked fine with DVI when I first installed it, prior to installing Mojave)
- Closing the Mac's case's lid
Eventually I tried going to Recovery (Cmd+R during startup), and to my surprise, the screen suddenly turned on, and I was presented with the Recovery options. I clicked on "Reinstall macOS", and annoyingly got a message saying I need to have a graphics card that supports the Metal API, and to have File Vault switched off.
Desperate, I tried the other options. I went to the Disk Utility. I somehow got to a menu that allows choosing which drive to boot from. I only had one option, my main drive, so I chose that. To my absolute shock, the Mac suddenly booted fine, and I was greeted with the lovely new Mojave
P.S. Tip for when installing the new graphics card: if the right edge doesn't go all the way into the motherboard, it's probably because the graphics card's metal leg has not gone into the Mac's case's metal hole, so just help it in.
Update
My GT 710 seems to have issues with two of its three ports: the HDMI has colour issues, and the VGA doesn't work at all. The DVI is the only port that works well. I am going to request a replacement from Amazon, and will update if it was just a faulty card, or if there is an issue with the model itself.
Update 2
Amazon sent me another GT 710 (brand new again), and unfortunately it has the exact same issues. So I can no longer recommend this card (unless you only care about the DVI port).
