So I got a 2019 27" 5K iMac, 3.7Ghz Core i5 machine. 3TB Fusion and 8GB RAM After transferring my stuff over from my old mac, I got a single core Geekbench4 score of 5580, then 21718 multicore. I added in 16GB (8GB x2) of Crucial Ram, and based on some things I read, I took out the 4GB X2 stock RAM and put in the 8GB in those slots, and the stock 4GB RAM into the originally empty slots. Ran Geek bench again and got surprisingly LOWER results 5332, and 23665 Multicore. Ran it over and over wondering why the single core scores dropped. Then decided to put the original RAM in the original slots they came in and the Crucial 8GB Ram into the empty slots. Got Single Core score of 6009, and Multicore 23529 Seems like a big difference and only thing that changed was the slots the RAM were in!