Choosing the right power supply for your computer

We write this article on "choosing the right power supply for your computer" to help you in your decision making process. Whether you are purchasing a power supply for your new computer or just replacing an old one we hope this will help in the selection process.

The first question to ask yourself is, "Is my power supply an ATX form factor?". If you have this information available then the selection process is much easier. The information is usually stamped somewhere on the power supply or may be contained in the manual for your existing computer. If you're looking for an ATX power supply make sure the power supply is an ATX form factor, not micro ATX or any other.

Another method to use in selecting a power supply is comparing the physical dimensions. Make sure your computer case can accommodate the the Height, Width, and Depth of the power supply. Take a look at the graphic above to gain a better understanding of Height, Width, and Depth.

After you have chosen your power supply based on physical dimensions you need to take a look at what connectors you need on your power supply. Different power supplies have different connectors so it's best to choose one with connectors that meet your every need. It's okay if you buy a power supply and not use some of the connectors. You can just leave them hanging unconnected. Below is pictures of some common connectors found on atx power supplies:

	ATX Connector - Shown in the picture is the ATX connector that inserts into an atx motherboard. This is the single most indicator of an atx power supply. If your motherboard has a slot for the 20 pin connector show in the graphic they you can be almost 100% certain that an ATX power supply is required for your motherboard. Be sure to pay close attention to the number of pins. On some Dell computers we've found that this connector contains 16 pins instead of 20. The only reason we can think of why Dell does this is to ensure that you buy a power supply from them and not anybody else!
	P4 Connector - Take a look at the 4 pin P4 connector shown in the picture. Most motherboards that have higher end Intel Pentium 4 processors will have a slot on the board for this P4 connector. If your motherboard has this slot then make sure you get a power supply with a P4 connector on it.
	IDE Connector - This is the IDE connector that supplies power to your hard drives and cdroms. Most atx power supplies have 4 connectors of this type included. If you need more than 4 connectors it's best to purchase y-splitters to increase the number of connectors. Purchasing power supplies with more than 4 connectors can often be much more costly than purchasing a y-splitter.
	Floppy Connector - The 4 pin floppy connector supplies power to any floppy drives that may be on your computer. Some of the card reader drives use this connection also. Most atx power supplies have two of these connectors included.
	AUX connector - Look on your motherboard and see if there is a slot that accepts the 6 pin AUX connector. If there is a slot for it then chances are you're going to need it.

 

You need to know how much power you're going to need. It's okay to buy a power supply that is larger than necessary because the power supply will step down to your power requirements. Buying a power supply that is too small for your requirements will be annoying. Many times people will complain of their computer rebooting for no reason at all. Nine times out of ten the reason for this is an undersized power supply. Many companies that sell computers will install an undersized power supply to save money and increase profit margins.

Below is a sample specification chart that should be printed on the sticker on your power supply. Before you buy a power supply make sure the power specifications are equal to or greater than your need. This way you'll avoid trouble down the road.

Lastly, we provide you with a table of suggested power supply wattage based on computer system size. Please note that this table reflects our opinion only:

Processor size	# of hard drives	# of cdroms	Suggested Wattage
< 1.0 Ghz	1	2	300
1.0 - 1.5 Ghz	2	2	350
1.5 - 2.0 Ghz	1	2	400
> 2.0 Ghz	2	2	430
> 2.0 Ghz	> 2	> 2	530

Be sure to see our articles on choosing the right computer case for your computer and how to install a front usb adapter.

We hope you have found this article both informative and interesting. If you require additional information on choosing a power supply please email us.

Disclaimer: This article is for information purposes and reflects only the opinion of the author. The sole responsibility rests with the buyer when selecting a power supply for a computer.