Why is it that my GPU and CPU usage are always very low when I'm gaming. I feel like playing on 180 fps is the same as playing on 30 fps because it is so choppy. Can anyone help me?

Whenever I play league of legends, CSGO. My GPU usage spikes so many times it goes to 99% and then back down to 0%. My CPU usage is always hovering at 30%-40%. Can anyone tell me why? I'm not enjoying game play at all at the moment. My GPU is a rx 460, and my CPU is AMD athlon 880k.