I have a 2009 Mac Pro 4,1 Quad Core 2.66 (without 5,1 firmware upgrade) running 10.10. I've been afraid to upgrade in fear of compatibility issues with my current set-up. Now it's hard to get anything new due to this old OS. What is the latest version of Mac OS that can support that platform? And how would I get it?
Also, is there a way to equip this 4,1 with more than 32gb ram? (I attempted booting in 64bit but it didn't read extra ram sticks)
Mac Pro, OS X 10.10
The 2009 4.1 MacPro can only officially upgrade to Mac OS X El Capitan, How to upgrade to OS X El Capitan – Apple Support
Of course if you did the firmware upgrade so it effectively became a 5.1 you could upgrade it to High Sierra.
How to upgrade to macOS High Sierra - Apple Support
And if your MacPro had a suitable, 'Metal' capable graphics card then you could upgrade to Mojave.
How to upgrade to macOS Mojave - Apple Support
As for the RAM you can install have a look at this from EveryMac,
if you scroll down to the Standard RAM section, it gives you details of how far you can upgrade this.
The 2009 4.1 MacPro can only officially upgrade to Mac OS X El Capitan, How to upgrade to OS X El Capitan – Apple Support
Of course if you did the firmware upgrade so it effectively became a 5.1 you could upgrade it to High Sierra.
How to upgrade to macOS High Sierra - Apple Support
And if your MacPro had a suitable, 'Metal' capable graphics card then you could upgrade to Mojave.
How to upgrade to macOS Mojave - Apple Support
As for the RAM you can install have a look at this from EveryMac,
if you scroll down to the Standard RAM section, it gives you details of how far you can upgrade this.
OS version Question
