Many features in this game are GPU dependent which will cause your GPU to show 100%, its fine... as long as your FPS is good and performance.. This is common for games today. I work in this industry. More and more, all of our development for game development also is GPU bound, which causes it to be at 100%., Substance, Modo, Maya, etc.. as well.. Back in the day a lot more was CPU, dependent , now its more GPU. which is faster and smoother. So your fine.

Be sure to monitor, temp on GPU, and CPU.. and make sure nothing is over heating ever, something developers, gamers a like do a lot .. Tech has changed. IN Unreal, tech is changing even more, so be ready to play games with the new Tech for Nanties, where we can have BILLIONS of tris on the scene at once..

which will be like that all the time as well..