I also have the same SSD (850 Evo 250gb) and I encountered both low IOPS scores and high (97000/88000) IOPS scores on my system
low IOPS score happens when App Center (set of utilities from Gigabyte motherboard "Easy Tune" and "SIV") is running in the background.
Luckily out of an unfortunate event after I update the MB BIOS it make the App Center out of date and unable to run.
That is when the high IOPS scores happens.
So, the 850 Evo really does the 97000/88000 IOPS without RAPID it was just being used, while with RAPID enabled it goes unreasonably high scores...