I’m not a big believer in “the universe is just a computer simulation” theories, but consider this: Assume that the basic chunk of computation is calculating one phase cycle for one subatomic particle. From Einstein, Planck, & de Broglie we know that mass = energy = frequency. So conservation of energy equals conservation of frequency, which is the same as saying that the total computational load of the universe is constant.
The universe is a simulation?
Energy and Time 