Opening F-secure SAFE or when it opens itself it makes screen go slower FPS or HZ if you have enabled 144-165Hz in your display. Is there solution to fix this or is the GUI designed for lower Hz?
Try turning the gaming mode on:
A pop-up menu appears.
The product's use of system resources is now optimized so that games can run smoothly on your computer.
The gaming mode reduces the product's impact on your computer and reduces its network use. This way, it frees up more system resources for computer games while still maintaining the essential functionality of the product. For example, it suspends automatic updates, scheduled scans and other operations that may need a lot of system resources and network traffic.
This is the 1st time I've heard anything like this. This is most likely something we can't directly do anything as this sounds like the problem of the UI framework (WPF) we are using. I did a web search and found https://github.com/dotnet/wpf/issues/2294. Does that look like a same issue?
One option you could try is disabling hardware rendering. Check https://docs.microsoft.com/en-us/dotnet/desktop/wpf/graphics-multimedia/graphics-rendering-registry-settings?view=netframeworkdesktop-4.8&viewFallbackFrom=netframeworkdesktop-4.8. for instructions how to do that. And please report back the results.