Update: Nvidia sent us a statement: "We are aware of a reported performance issue related to Game Filters and are actively looking into it. You can turn off Game Filters from the NVIDIA App Settings > Features > Overlay > Game Filters and Photo Mode, and then relaunch your game."

We have tested this and confirmed that disabling the Game Filters and Photo Mode does indeed work. The problem appears to stem from the filters causing a performance loss, even when they're not being actively used. (With GeForce Experience, if you didn't have any game filters enabled, it didn't affect performance.) So, if you're only after the video capture features or game optimizations offered by the Nvidia App, you can get 'normal' performance by disabling the filters and photo modes.

So, TomsHW (is at least claiming that they) did indeed test this, and found that its the filters and photo mode causing the performance hit.

Still a pretty stupid problem to have, considering the old filters did not cause this problem, but at least there's a workaround.

... I'm curious if this new settings app even exists, or has been tested on linux.