Difference between CPU Utility and GPU Utility

We can observe CPU and GPU utility from htop/nvtop. As far as I know, GPU utility is measured from average use of GPU resources (arithmetic, logic, memory) over a period of time. Frequently being used does not ensure high GPU utility. I am wondering if the way CPU utility is calculated is the same as GPU utility. Does htop consider average use of different RESOURCES, or just count if it was used at sampled time instants?