Building a Low-Power Home Theater PC System

The Antithesis Of "Bigger Better Faster More"

Many users perceive the ultimate Home Theater Personal Computer (HTPC) as nothing more than a fancy file player. Certainly, having the ability to convert files from one format to another would be nice, and being able to watch a stored movie while transcoding another is handy, but considerations of heat and noise have kept market expectations low.

While examining AMD’s low power Athlon 64 X2 3800+ Energy Efficient Small Form Factor CPU we came up with an idea. Rather than simply testing and shelving this nice hardware, why not put it to use ? As we examine the hardware we’ve chosen, we’ll also consider a few changes that could bring additional functionality to your next HTPC build.

Component Selection

Processor

A cool-running processor is the first step toward minimizing system noise. AMD made our selection simple by sending us its 35 W Athlon 64 3800+ Energy Efficient Small Form Factor (henceforth abbreviated EESFF) CPU.

Several alternatives for those attempting to meet even lower heat or budgetary targets include mobile cores, single cores, and under-clocked standard parts. Intel’s Core 2 Duo Mobile processors exemplify the highest-performance low-wattage solution, and the single-core Athlon 64 consumes far less power than similarly-clocked Athlon 64 X2. Under-clocking is easily accomplished on many Athlon 64 platforms by simply dropping the core multiplier, allowing a lower voltage selection to remain stable.

Motherboard

Our needs here were simple : we wanted a platform that could supply clean video at moderately-high resolutions to an HDTV, consume a minimal amount of power, and support our chosen "EESFF" CPU. We found all of this in the Asus M2NPV-VM.

Onboard GeForce 6150 graphics consume so little power that the Northbridge can be passively and silently cooled, even at a high enough performance level for viewing MPEG2 and MPEG4 video at common 720p and 1080i resolutions. Buyers looking for more audio or fewer video connections can certainly find these in the wider selection of Socket AM2 motherboards available from several manufacturers.

Moving up to a Core 2 Duo Mobile processor limits onboard graphics power to less capable Intel solutions, which could result in a system that can transcode video files more quickly but at lower viewing resolutions. This probably won’t be a problem for owners of common 1366x768 flat panel displays, nor for anyone adding a graphics card into the initial build. Universal Abit, AOpen, Asus, ECS and MSI are pushing Mobile On Desktop into home theaters, the first adding HDMI output and others offering a PCI-Express x16 expansion slot.

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Thomas Soderstrom
Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.