Power Delivery

Nothing moves much without power, does it? It's the simple law of thermodynamics. Energy In = Energy/Work Out. To a large extent, the power system also determines the stability of the motherboard. The more stable and closer the power is to the perfect DC levels, the better a processor should perform.

To do that, motherboards use a slew of voltage regulator modules (VRM) and power width modulators (PWM), usually in a single package. I would like to remind you though that there are many different power delivery systems out there that do not conform to this mould, but I'll try my best to explain the most popular ones and how to determine if a motherboard has a good power delivery system.

The motherboard power supply is based on the voltage regulator module (VRM) which works on the basis of power-width modulation (PWM) control. I can't tell you exactly how PWM control works since I'm more partial to working with linear regulators and LDOs but I'll give it a shot anyway.

What PWM does is control the supply of electrical power by modifying the pulse width by increasing the duty cycle. The pulse width is like the time the current switch is opened, and it is opened and closed rapidly depending on duty cycle to deliver the right amount of power to the load. For more information on PWM, you can check out its Wikipedia entry.

PWM & Regulator Quality

If you actually peel off the heatsinks that cover most of today's PWMs and look at the part numbers, you can actually compare them by a few specifications which I'll list below. I'd like to note that this section may not be too accurate since I have no working knowledge of PWMs. Like I mentioned earlier, I'm a linear and LDO man.

Load Accuracy - This is the accuracy of the voltage under it's full load, the smaller the number here, the more accurate the output should be and the better it should be for your processor.

I_o : This is current output - the maximum current in amperes that a component can deliver. Obviously, the higher the current output, the better; even if your processor does not use that current. I will use a simple analogy of a common sedan and a sports car. If they are both being driven at 150 km/h, which car's engine would be under greater stress? I'm sure you get the idea.

Switching Frequency : The faster, the better obviously. This allows the PWM to quickly switch to a different duty cycle state.

Peak Switching Voltage : When most PWMs switch, they create a sudden voltage spike. Voltage spikes are not good for any electrical circuit, much less one that runs through a delicate motherboard. So, the lower this voltage is, the better.