that i can't say i'm literate enough as some of these folks to respond totally intelligently - i'm told and have read the 950 PRO is better suited for client applications vs enterprise, which the intel 750 is supposed to be.
Main reason i went with the 950 was a) price and b) the write speed on the 512 GB variant was 1500+ MB/s vs 900 for the intel 750
I was hoping for reduced render times when rendering large video files - times had dropped from 65-85 minutes for a 34-36GB file to 28-36 minutes with a samsung xp941 (first gen, PCIe 2.0 x4). With the 950 i didn't see any further drop in times, which told me the cpu was the bottleneck (it was and always has shown 99-100% usage while rendering, this on a i7-4790 w 4C/8T.
What really flipped me out, was enabling rapid mode in samsung magician bumped a 2 yr old 840 to about 2+X faster benchmarks than the 950 - see below, and sonuva BMT, when i cloned the 950 back to the 840, and booted the system off the 840, it definitely seemed "snappier" in every way - opening software, etc. I haven't tried it rendering yet but we'll see. 2nd image below is the 840 benchmarked.
But it did make me wonder the "bang for the buck" i didn't get or expected more - i hadn't enabled rapid mode in samsung magician earlier as there had been reports of conflicts.
btw, i only knew or recognized your issue as i'd experienced with my first 4TB HDD - windows in MBR just doesn't recognize anything over 2TB