Building a cheap Blu-ray PC: AMD-based

We are building a PC to watch movies via DVD & Blu-ray discs since component prices are now low enough to justify doing so. Of course, this PC can do gaming, surf internet & do all stuff that other PCs can do as well.

A complete Blu-ray HTPC system sold by a famous brand currently cost US$1000, comes with 22" LCD monitor. If we build one ourselves (or get a computer shop to assemble for you), the cost is not only lower, but the specs are better as well.

We have done extensive research and we are able to assemble a decently-priced PC (exclude LCD monitor) to play 1080p quality Blu ray movies on a decent budget of US$650 (motherboard, MOBO + 2G memory + 160G harddisk drive, HDD + 450 W power supply + AMD Phenom II X2 555) + Blu Ray ROM drive.
The motherboards (MOBO) we choose is the Gigabyte's 790GX / 780G series, GA-MA785GM-US2H . This MOBO comes with 3D overclocking performance [boost the GPU frequency up to 950MHz] that delivers a rich, High-Definition home theater entertainment experience and delivering unprecedented UMA graphics performance with a 3DMARK06 score of 2000 or higher*. At of the heart of the MOBO lies the ATI Radeon® HD4200 graphics core, featuring support for DirectX® 11, Shader Model 4.0 and OpenGL2.0 as well as meeting the official HDMI 1.3 certification. High-Definition multimedia support is carried throughout the Radeon® HD 3200 outputs, which include not only D-Sub and DVI, but also HDMI to support numerous monitors. This MOBO meet the HDCP specification for output protection management and security specifications of the latest Blu-Ray™ media format. Featuring support for ATI's Avivo™ technology, the GIGABYTE's 790GX / 780G provides ultra smooth playback of the latest Blu-Ray™ HD content, and with support for the innovative ATI UVD™ technology, provides spectacular picture clarity at resolution up to 1080p for incredibly fine image quality. The MOBO is equipped with the built-in High-Definition 7.1 + 2 channel Realtek ALC889A sound chip, whose 106dB signal-to-noise ratio significantly reduces noise during signal transmission and supports Full Rate Audio support for Blu-ray™ HD media. Gigabyte also supports Dolby Home Theater, giving our PC another powerful set of tools to deliver a cinema-style experience in vivid surround sound.

So with good graphics and audio on the MOBO, we save money on having to buy separate graphics card & sound card. Next, to maximise the potential of this MOBO, we put in 4G DDR2 dual channel RAM [1066 MHz]. Then we add in a 450W power supply for power stability. And of course, we use the fast SATA-based drives: HDD & Blu Ray ROM drives.

The main components:

AMD Phenom II X2 555 Black Edition Callisto 3.2 GHz 2x512 KB L2 Cache Socket AM3 80W Dual-Core Processor - Retail HDZ555WFBGMBOX

Gigabyte GA-MA785GM-US2H Micro ATX Motherboard

Coolermaster 430W power supply unit
Seagate Barracuda 320GB SATA Hard Drive
Kingston HyperX Memory 2GB 1066MHz DDR2 PC2-8500
Liteon 4X Blu Ray ROM Drive
Coolermaster Mini Tower PC Chasis
Antec Fusion Black 430 Desktop PC Case with 430-Watt PSU