Low power PCs have been something of a trend lately, and the trend has manifested itself strongly in the HTPC arenas. HTPCs are a natural candidate for a low-power PC. Lower power consumption usually results in less heat, less noise, and lower electric bills. There is, in other words, a lot to like.
This guide will help you select the components needed to build a low-power HTPC. This guide does not deal with assembly, which does not differ significantly from any other PC. For assembly instructions please see our guide to assembling a PC.
Power to a Point
Every component in a PC uses some amount of power. Some, however, use significantly more than others. A typical mechanical hard drive, for example, will use between 5 and 10 watts of power. A video card, on the other hand, might use 50 watts even at idle. This means that when building a low power HTPC it is best to focus on the areas where the most power savings can be had. The two primary areas are the processor and the video card.
The relative power usage of a processor can be determined at a glance by looking at the advertised TDP of a processor as measured in watts. The lower, the better. For a low-power HTPC, you’ll probably want a processor with a 45 watt TDP or lower. This excludes the most powerful parts, but the processors which fit into this power envelope are more than adequate. If you wish to have extremely low power consumption, you could build your HTPC around a dual core Atom processor. Performance will suffer, however.
Video cards don’t provide any easy indicator of their power consumption, so choosing the right one can be difficult. Generally speaking, however, you’ll simply want to choose the best small video card available. Absolutely avoid video cards meant for gaming, as they are by far the most power hungry. My personal favorite is the Radeon 4350, as it is small, inexpensive, and very easy on power draw. Also make sure the video card has an HDMI output for easy connection to an HDTV.
Simply choosing a low-power processor and video card will allow you to build a PC which is much lower in power consumption than most PCs on the market. However, if you want to shave off every watt possible there are a few other things you can do.
Power supplies are one area when power can be saved. Different power supplies are rated differently for efficiency, which refers to the difference between the power the power supply draws from your socket and what is supplied to the components. For example, a power supply running at 80% efficiency will draw about 240 watts of power from a wall socket in order to supply 200 watts of power to the components inside. Choosing a power supply which is very efficient will help conserve power.
Choosing a smaller motherboard can also help save power. Generally speaking, two motherboards using the same chipset will draw a similar amount of power. However, mATX and mITX motherboards tend to draw less power since they have fewer components on the board. This can save several watts of power.
Finally, the hard drives you choose can save your some power. Choosing a low-performance 4,200 RPM drive or a solid state drive can save you several watts per hard drive.
Following this advice for picking the hardware of a low power HTPC will give you a computer capable of all the functions one expects from an HTPC which also draws very little power.
If you wish to further save power, however, there are software options for which can further reduce power consumption. For information regarding this, please see our guide on configuring your computer’s power options.