Understanding Computer Power Supplies - PSU of the Future

Understanding Computer Power Supplies - PSU of the Future
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Since the birth of computers, technology has been progressively been getting faster and more energy demanding. To quench this need for power, power supplies have been getting larger. Power supplies convert high voltage alternating current, AC, from the wall, to lower voltages of direct current, DC, which computers and electronics can use. See our guide to Understanding Power Supplies.

For most users, a 300W to 400W power supply is ample to support today’s system. Even for the most power-hungry of game systems, 700W is more than enough for a quad core processor and multiple graphics cards. This however has not stopped manufacturers from designing “bigger is better” computer power supplies with more bells and whistles.

Photo by: William Hook

Larger Wattages

As previously stated, on average, power supplies have been getting larger to support more powerful computer hardware. Some of the largest power supplies exceed 1500W (Ultra’s 1600W X3) and can deliver more than 1400W to the +12V rail alone (which is utilized by the CPU, motherboard, and graphics cards). These larger wattages though have become more of a selling point gimmick since the average user is using nowhere near 1600W of power. You should find out just how much power your computer needs before spending excessive amounts for hardware you simply do not need.

Find out how much you really need with this power supply calculator.

Smaller Wattages

On the other end of the spectrum are smaller wattage power supplies which emphasize high efficiency (more on this in a second), low power, quiet performance. These power supplies are moving in a more reasonable direction offering what the consumer needs in a cost saving package. These power supplies however are not lacking. They deliver what is needed, and no more, to those desiring smaller, quieter, and cheaper systems.

Multiple or Single +12V Rails?

Recently, it was though that multiple (quad and dual) +12V rails for power supplies could deliver power that is more consistent. In addition, with high wattages, this is also a gimmicky selling point that more is better. Without going too in-depth, this myth has since been dispelled since multiple rails can sometimes be deficient in delivering the necessary power. There are a few exceptions, but a single rail (one +12V rail) is now the accepted standard and what you should be looking for in your next PSU. A single +12V rail does not split the current so that there is no shortage or need to balance the load on the PSU. In short, it makes life easier.

Modular Power Supplies

One of the most welcome and popular advancements in the power supply unit (PSU) are modular plug cables. These cables reduce computer case clutter to improve air flow, reduce temperatures, and give a cleaner, more organized look. They allow you to customize cabling to meet your needs and use only the cables that fit your components.


The last and most beneficial advancement in power supplies is a jump in efficiency ratings. It used to be the de facto standard of efficiency was the 80Plus designation. Now, PSU makers have reached the 90% efficiency mark and have been steadily improving. A higher efficiency means less wasted power. The rating is the ability of the unit to deliver to the computer the same amount of power it draws from the wall. A higher efficiency means less heat (wasted energy) and electricity bill savings. Efficiency usually peaks at 40%-60% power draw meaning that a 1000W power supply is most efficient when 400W to 600W is being utilized. That is why it is terribly wasteful to buy a 1500W power supply when you only plan to use 400W to 500W.

Power Supply Bricks

This wouldn’t be a guide of the future without mention of those little laptop bricks. As laptops and small netbook and nettop computers become more popular, power supplies have been shrunken into a small brick. These perform the same duties as a desktop power supply, converting AC to DC. The reason they are so small is that they deliver less power and need to be portable.


Today we have looked at the up and coming features of the latest and future power supplies. I hope that this will give you an idea of what to look for when comparing power supplies.