It is not only a problem with ryzen, I also have a low usage with my 1060 6G and I7-4790
The issue isn’t you graphics card or how Ironsight is using it but it’s your Ryzen CPU.
Ironsight has some minor issues with Ryzen CPUs. The developers are aware and working on it.
You can try switching your CPUs performance to „high performance“ in the AMD Ryzen Master tool.