iMac 27-inch (Retina 5K) 3.1GHZ 6-Core i5 (2019). - Apple MRR02LL/A. The iMac "Core i5" 3.1 27-Inch Aluminum (Retina 5K, 2019/Coffee Lake) features a 14-nm "Coffee Lake" 3.1 GHz Intel "Core i5" processor (I5-8600) with six independent processor "cores" on a single chip, a shared 9 MB level 3 cache, customize your hard drive and memory, and a Radeon Pro 575X graphics processor with 4 GB of dedicated GDDR5 video memory. It also has a built-in "FaceTime HD" webcam and stereo speakers.