Nvidia has acknowledged the problem of FPS drop in the new NVIDIA App and is already working on fixing it
The recently released NVIDIA App, which replaced GeForce Experience, has been found to be causing performance issues in some games. Gamers report a decrease in FPS of up to 15% when the program is actively running, especially when using the Game Filters and Photo Mode functions.
The problem was first brought to the attention of Sebastian Castellanos, and Tom's Hardware confirmed it, by conducting independent tests. It turned out that the decrease in performance is mainly due to the inclusion of filters. If they are disabled, there is minimal or no performance loss.
NVIDIA has acknowledged the issue and recommended temporarily disabling Game Filters and Photo Mode. You can do this like this:
The company is already working on a fix and promises to release a hotfix in the near future. It can either completely disable the problematic feature or prevent it from being enabled automatically.