This of course highly depends on your CPU but the point here, is that it uses the full power of your GPU, and seeing a performance loss with OBS on Linux is pretty common.

In their own testing, they said they saw FPS drops from 30 to 7 with OBS Studio at 4K but with their tool they saw a solid 30FPS. This means that CPU usage remains at around 0% when using this screen recorder. This gpu-screen-recorder keeps the window image on the GPU and sends it directly to the video encoding unit on the GPU by using CUDA. OBS only uses the GPU efficiently on Windows 10 and Nvidia. These operations are very slow and causes all of the fps drops when using OBS. OBS only uses the gpu for video encoding, but the window image that is encoded is sent from the GPU to the CPU and then back to the GPU. Why make it? Well, in their own words on how it's different to OBS when paired with NVENC:

They claim it's the 'fastest screen recording tool for Linux'. It doesn't have a fancy name, just called ' gpu screen recorder' along with GTK front-end you can use to help manage it. Find you get too much of a performance hit using other recording tools like OBS Studio? Maybe this new tool will help.

Nvidia shadowplay recording