I have a mac pro 4.1 upgraded to 5.1 currently running High Sierra. I just got a Sapphire RX580 pulse 8gb card. Is this plug and play or do I need mojave to run it? My original plan was to upgrade to Mojave but a friend just did this and now has black spots on his photoshop images. Apparently many other photoshop users had this problem after upgrading mojave. Do I just remove the gt120 card altogether? Thanks for any advice?