Short story What memory is preferable: 24GB at 1600MHz or 16GB at 1867MHz? Long story We've got two iMacs (5K, Late 2015) with 8GB (2x4) 1867MHz CAS13 default memory. I've bought an additional 32GB (4x8) 1867MHz CAS11 memory. Turns out when I let both iMacs run on 24GB (2x4 plus 2x8) it bumps down the speed to 1600MHz due to CAS latency difference. An option would be configuring one iMac as 16GB (4x4) and the other as 32GB (4x8). This way they run both on 1867MHz since there's no difference in CAS latency. Runs an iMac better on 16GB 1867MHz or should I stay with 24GB 1600MHz for both models?