I've been playing The Witness, and I noticed that the game is lagging without fully utilizing my graphics card.
My setup is pretty old at this point (HD 5850 and i7-930). The game remained at a semi-steady 60fps on Normal settings, but there were a few hiccups while running or while quickly panning the camera.
However, my GPU load barely exceeded 60-70% while playing, and my CPU load was around 30%. I didn't see any spikes on the load chart (MSI Afterburner).
For comparison, I tried loading the game on High settings and my GPU usage was at 80+%. I also tried playing Minecraft the other day with a shader pack, and GPU usage sat at 90% the whole time with a steady (albeit <60) fps.
My question: is it normal for a game to lag if your GPU and CPU aren't under full load?