Latest Intel storage tool has a different exe. I used:
Elevated command prompt (Windows 10)
C:\Program Files\Intel\Intel(R) Memory and Storage Tool\intelmas.exe show -intelssd 0 (in my case my Intel ssd was the second drive so 1 instead of 0)
C:\Program Files\Intel\Intel(R) Memory and Storage Tool\intelmas.exe set -intelssd 0 Physpeed=6
Will need to powercycle the SSD.