Hello,
I just did an install of Mojave on my Mid 2012 Mac Pro with the Radeon RX580 card. I did speed tests using Cinebench and these are the results.
Sierra OS - ATI Radeon HD5870 - Score: 1647
Sierra OS - Radeon RX580 card = Score: 1590
High Sierra OS - Radeon RX580 card = Score: 1419
Mojave OS - Radeon RX580 card = Score: 1320
I thought this card with Mojave was suppose to be up to 8x faster. Its actually slower. Any reasons why ?
Thanks