marzrov Are you running the Nvidia App (or perhaps GeForce Experience), and have you allowed it to "optimize" your in-game settings? If so, please disable that option.
If that's not the issue, please change the graphics settings one at a time to see which one is causing the game to drop to the lowest settings. If it's all of them (or I guess a few in a row), that would also be useful information.
I'd like to see a dxdiag as well. Click Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.