If I look at the results of a test, say Manhattan, in GFXBench Metal for my M395X 4Gb, a few things puzzle me. 1) my 3128 frames is way down the list looking at the Compare with other devices tab, to the extent that it is below 21.5" late 2012 iMac (3305) and others which I would not expect. 2) if I look at the ratings here the same card appears pretty high up the list. Is this a different spec to the iMac 5k version? I'm confused!