MHz is known to stand for Megahertz. The main goal of this is to make sure that the actual speed of the different devices that are available can be measured accordingly. Aside from the devices, this will also be in charge of checking out the different channels, the buses, and the internal clock of the computer. When you say Mbps, this is in charge of checking out the number of bits that are being transmitted through different forms of media.
For example, you would like to know if this is available for the fiber optic cable. This is definitely something that you have to understand so that you will know their differences and how they work.