The Samsung 950 Pro is the successor to the Samsung SM951 and their first retail M.2 drive. While this drive does run cooler than previous M.2 drives from Samsung, it still has some throttling issues due to high temperatures. Even with that, this drive has incredible sequential read and write performance at an attractive price point.
The Samsung SM951 is the successor to what was at one time the fastest consumer M.2 drive – the Samsung XP941. This drive has incredible sequential read and write performance, but suffers from extremely high temperatures under load.