OBS supports Nvidia Shadowplay up to 120FPS.
Adjust the settings in OBS Advanced Settings.
I checked the location earlier tonight and found it running at 30 frames per second, but I managed to boost it to 60 FPS.
The advanced options include a feature for capturing up to 120 frames per second. I just installed OBS and tested it, and it works as expected.
I don't understand why you're feeling that way.