The 2019 27 inch seems to be working great... when I go under "about this mac" and view memory, the top two rectangles show the ram I put in (two 8 gb sticks) and the bottom two rectangles show the ram it came with (two 4 gb sticks). I read on here that that was correct installation pattern? The 2010 had more troubles... I took out the old ram (two 2 gb sticks), and put the new and old ram back in so it would have the same pattern as the 2019 iMac. At first when I would turn it on it would just beep three times every five seconds... but once I took the ram out and reinserted it a couple of times it has started up fine every time (2-3) starts... Question is: should I worry, or does this mean whatever issue it was having, it os working now? Any input is good input... thanks! Oh all new ram is OWC for both computers?