I too am have trouble with my 750 PCIe NVMe SSD, which I also use as my boot drive. Sometimes, my system won't post, and I have to go through the entire system of booting in UEFI on an USB drive, loading the drivers until it recognized my 750, and then I can try repairing the drive or restore the drive to an earlier point in time.
Earlier today when I got back to the house, my system and been on for a couple of hours, no one has touched it. but under My Computer is shows the 750 Drive, my C Drive with my OS installed, 100% full. It does this randomly, and usually I just need to open the Intel SSD Toolbox and run the Intel SSD Optimizer and it fixes all my problems.The drive itself is full of these files, --=={Intel_Trim_File_3}==--, which means the drive obviously isn't running TRIP the way it's supposed to, but I've setup a schedule for the Intel SSD Toolbox to run the SSD Optimizer every evening.
Again, in addition to these problems, the drive doesn't seem like it's running as fast as my Samsung 850 EVOs setup in RAID0. Not sure if one has something to do with another, maybe I missed installing a driver for the 750 PCIe SSD, or something, but I've been having issues recently as well.