Specs Dictionary

Voltage regulation is how well a PSU responds to load fluctuation in terms of how voltage adapts to these changes. A PSU will have the 12v, 5v, and 3.3v rails all fluctuating in voltage levels depending on the load and temperature of the PSU.

Voltage ripple is small amounts of voltage fluctuation in a short period of time. Voltage ripple is measured peak-to-peak (waves) and usually usually reported in mV. Voltage ripple varies across rails, and both temperature and load impact voltage ripple.

Different regions have differing AC voltages (from wall outlets). The United States and a few other countries use ~120v, whereas the rest of the world mostly uses ~220v.