The I7 2600 S will work all the way up too High Sierra. While you'er in their add a pair of Samsung SSD 's and run them in RAID 0 config (Either take the optical drive out and use the spare SATA port or pull the HD) and max out the RAM. You'll think you'er using a 2017 system! The speed is amazing. I built one a little while ago and I'm about to build another. Oh, by the way use a high quality thermal paste on the CPU and GPU chips while your in there too. Have fun... Gerard