Is your computer power supply causing problems?

The power supplies found in most computers are extremely cheap, a fact that ends up being the cause of a lot of computer problems. This means that it doesn’t make too much sense to replace one cheap unit with another cheap unit, even if the replacement has a higher wattage rating.

Every time I encounter a problem that seems to have no reasonable explanation (on a desktop PC, that is), the culprit has been the power supply. Say, all of a sudden, one of your storage devices (hard disk, tape drive, etc.) starts malfunctioning, either sporadically or completely or your computer just blinks when you try to turn it on.

You try removing and reinstalling the drivers (if any), you replace all the cables, and you take out all the other devices. You may even completely replace the device with a brand-new one—and it still doesn’t work. Odds are your power supply needs to be replaced. Make sure to read our post on troubleshooting power supply issues.

Your computer’s power supply runs all of your internal devices, as well as some of your external ones (i.e., the keyboard, the mouse, and most USB devices). If your power supply isn’t able to provide adequate power to all your hardware, one or more of those devices will suffer. Be sure to read out previous post on how to reduce the amount of power your PC uses.

Power supplies are rated by the amount of power they can provide (in watts); most computers come with 200–300W supplies, but many power users end up needing 350–400W. The problem with power ratings, however, is that most of those cheap power supplies don’t hold up under the load.

A cheap 400W unit may drop under 300W when you start connecting devices, but better supplies can supply more than enough power for even the most demanding systems, and will continue to provide reliable operations for years to come.

A well-made power supply will also be heavy and have multiple fans, as well as being a bit more expensive than the $20 or less type. Possible exceptions are laptops or netbooks, which may not have user replaceable power supplies. However, the need for increased power is generally only applicable to desktop systems.