Yet another computer random crash, unstable behavior or are you unable to reach that overclock target of yours? Then read this article about power supplies, I’m sure you’ll learn at least one or two essential things about them.

The majority of computer users today just use the power supply included with the case they buy. It comes with it, so it must be good right?

Well, let me put it this way. When you buy a let’s say, 70$ case that comes with a power supply, how much of that 70$ goes into the power supply according to you? Not much, eh? You would be right and with computer hardware, you usually do get what you pay for.

The problem these days, is that there are so many different power supplies models from so many brands, it is really easy to get lost by trying to choose one yourself.

Here are the reasons you want to buy your own power supply, and choose it yourself: You want to ensure that your power supply :

  • Delivers enough power to all your hardware parts and have some overhead, in case of intense utilisation. That is calculated with Watts(W) and Amperage (A). Most power supplies brands put heavy marketing and emphasis on Watts, but both units are just as important what choosing a power supply.
  • Delivers stable voltage, so that your computer does not crash due to voltage spiking. This is ESSENTIAL when you overclock. You want clear, clean, stable current. After all, the last thing you want is your computer crashing in the middle of some important work right? That’s what I thought 🙂
  • Protects your computer in case of thunderstorms, faulty electrical wiring, power surges, spikes and such. If for some reason, the voltage in your electrical line spikes or drop, a no-name power supply will simply pass it on to your computer. You’ve just set yourself for another computer crash or if you’re unlucky, some nice fireworks inside your computer. A good power supply will take the hit and protect the rest of the computer by doing so. I rather lose a 100$ power supply than a 1500$ computer, what about you? Especially if you have critical data on your hard drives!
  • Is efficient: An efficient power supply will consume less electricity, produce less heat and in general, will also be more silent.
  • Will provide better cooling for your case. Good power supplies are usually equipped with a large 120mm or two 80mm fans.

Alright, are you convinced now? If not, maybe this will. This is a story of my own experience.

I had built a very nice computer, with mainstream parts, running very well. I was pleased. Then I decided to upgrade to water-cooling, that is cooling your computer with a radiator, a pump, a water block, usually a reservoir and of course, water. Similar to car cooling. I did a test run, with most of the parts outside the case, with the computer being off, to make sure nothing was leaking. Everything was fine, so I went ahead and installed everything in my case and kept my case open to refill the system later on.

I replugged the computer and switched the power on, while laying down on the floor to keep an eye on all the tubes and parts, to make sure absolutely nothing was leaking. Everything seemed to be fine, so I looked at my screen, to check on the start-up of Windows, to ensure it was fine. That took maybe 3 seconds and as soon as I looked inside of my case again, I just saw that drop of water, falling from the video card water block, heading straight for the inside of my power supply (which had a 120mm intake fan on top). I didn’t have time to react, I just panicked for half a second, until the water reached the inside of the power supply. I saw sparks flew by inside of the power supply, it actually caught on fire inside! Then it just shutdown all by itself and the fire stopped. It smelled like burnt parts. Now, I had an OCZ GameXstream 600W power supply, which is considered a quality power supply. If I had a no-name power supply, the power supply would have kept running, until it melted and couldn’t function anymore. That is, until the whole case would have caught on fire…

I knew that would have convinced you.

So, back to what you want for your computer. First of all: How many Watts do you need? This will depend on the system you intend to build, if you want to overclock and a lot more factors. Here’s a power supply calculator I can recommend to you, that I have used over the years and I know that a lot of overclockers use it too. This will give you a very good idea of your needs, for how many Watts you need that is.
Click here for the power supply calculator.

Next step, Voltages & Amperage: Only the +3.3V, +5V, +5VSB & +12V are used by modern computers. Spec is usually +/- 5%. When the original ATX spec was written the +3.3V and +5V were far more stressed by heavy usage demands than they are in today’s computers. Almost any high quality ATX spec Power supply of 300Watts or more can supply far more +3.3V and +5V amperage than today’s computers require. Today’s computers, especially the latest AMD Phenom’s/Athlon 64/X2 and the latest Intel’s stress the +12V rail the most, requiring far more amperage than was originally called for in the original ATX spec for the +12V rail. Video cards can be the biggest +12V resource hogs! Newer ATX12 V2.0 designs are creating ever more wattage on the +12V rail, to meet the needs of today’s & tomorrow’s computers.

I would worry about the Amperage rating on the 12V only, as this is what will be used mostly. You want 26A as a minimum for a single high-end video card system and 36A for SLI/Crossfire high-end systems. If you intend to use high-end video card, especially those with dual-gpus, I would recommend that you stick to a single 12V rail type of power supply. This will ensure that you will have enough Amperage on the 12V line to power your entire system. Power supplies with multiple 12V lines split the total 12V Amperage over the lines, which is not efficient for a system with a or some high-end video card(s).

Hold Up Time: Measured in milliseconds (ms) is how long the Power Supply will continue to supply in spec voltage & amperage, once the AC input voltage is removed. The longer the hold up time generally the higher the quality of the Power Supply. Hold up time gives the time necessary for an Uninterruptible Power Supply (UPS) to switch to batteries and allow uninterrupted operation of the computer.

Efficiency and Temperature: There are no electronic devices that are 100% efficient & Power supplie’s are no exception. Typically PS’s operate between 60% and 85% efficiency. The more efficient the PS, the less power that is lost as heat and the lower the cooling requirements. Newer PSU(Power Supply Unit)’s meeting the ATX12V 2.xx specs have efficiency ratings from 70% to as high as 85%. The “80%+” certification requires 80% or higher efficiency.

Regular vs Modular power supplies : Modular power supplies are designed so you can only plug the wires that you need for your power supply. Which is great, I mean, who never had to hid all those extra wires that we didn’t use. It sure makes things look cleaner, less messy and it improves the airflow! I recommend going with a modular power supply.

Here are my recommendations for power supplies. I included links to a canadian retailer if you want to buy a new power supply right now. All the power supplies recommended here have a single 12V rail, to ensure you have no problem with high-end video cards or SLI/Crossfire. Unsure of how many Watts your system needs? Check it this link for a power supply calculator: Click here for the power supply calculator.

If you need 400W or less:
Ultra X-Connect 400Watts Power supply. Modular, 20A on the 12V. 36 months Parts and Labor Guaranty. Perfect for someone on a budget, building an office system, etc.
Click here to check it out and buy it at 48.99$

If you need 500W:Ultra X-Connect 500Watts Power supply. Modular, 28A on the 12V. 36 months Parts and Labor Guaranty. Click here to check it out and buy it for 60.99$
If you need 600W:
Ultra X Pro 600Watts Power supply. Regular type, with 36A on the 12V. 36 months Parts and Labor Guaranty. Click here to check it and buy it for 109.99$
If you need 700W:
Ultra LSP 750Watts Power Supply. Regular type with 45A on the 12V. 33 months Parts and Labor Guaranty. Click here to check it out and buy it for 121.99$
If you need 800W:
Pc Power & Cooling Turbo Cool 860Watts Power Supply. Regular type, with 64A on the 12V. 85 Months Parts and Labor Guaranty. Click here to check it out and to buy it for 335.99$
If you need 1000W:
Ultra X3 1000Watts Power Supply. Modular type, with 70A on the 12V. 36 Months Parts and Labor Guaranty. Click here to check it out and buy it for 365.99$

What do you think? Anything to add?
As usual, feel free to ask your questions and shoot away your comments, both in the comments section.
I hope you enjoyed reading this article as much as I did by writing it. If you did, dig it, link it on your blog, talk about it with your friends 😉
Cheers, Mathieu