I have a Mac Pro 5.1 from 2012, originally Quadcore. I wonder if it can run 12-core CPU which I already have installed? Or is the Quadcore not made for that? The processor from the beginning was 3,2 GHz Nehalem (I guess) with 6 GB RAM. Now I have 2 x 3,06 Ghz Westmere with 128 GB RAM. Above that I have also upgraded to MacOS Big Sur 11.2 via open core. When I use Adobe apps the computer is too slow. I get beach ball all the time in Photoshop and very heavy load on CPUs in Dreamweaver. It takes 1-2 minutes to be able to work in Dreamweaver. I guess the machine is obsolete. Apple dropped it from support in June 2019. Mojave was the last system with natively support if you changed to Metal-compatible videocard.