The [OC]Mod Blog

There are a few things you can check to make sure you’re getting a good power supply, no matter what brand. 

You must check the model identification sticker for the specifications of the individual channels. 

 

High school physics tells us that Watts = volts * amps.  If a PSU has 18A on the +12V line, then that line can output 216 watts.  The same PSU may have 45A on the +5V line, for 225 watts on that line.  Add the two together to reveal that this PSU should output 441 watts.

 

A good PSU will have at LEAST 18A on the 12V line.  Most of the important components in your PC use the 12V line (fans, CPU, hard drives, CD drives, other peripherals, etc).  A power supply may advertise that it is 500W, but still may brown out if you add too many peripherals because it cannot output much on the 12V line.

 

Some cheaper power supplies do not output the total wattage they say they do.  To verify this would require extensive testing that the average consumer is not able to do.  From the articles I’ve read, Enermax PSUs usually exceed their advertised wattage.  Quality PSUs are generally heavier, too, as they have more robust heatsinks.

 

There are other things to consider when comparing a PSU, such as wire gauge, wire length, cable sleeving, and additional fans, but I’ve found that a PSU with a good rating passes these considerations.

 

Tom’s Hardware Guide has a good article that compares 21 different power supplies.  You can reach it here:

 

Hope this info helps someone make a more informed decision when choosing the often-overlooked power supply.