Choose the right HD graphics card

Playback of high-definition (HD) video has already become a killer application for PCs.

While dual-format Blu-ray and HD-DVD players are rare, and there are few consumer options for streaming or downloading HD content from the internet, you can achieve all of this and much more with a single PC.

In previous Hardware and Performance columns we’ve explained how to equip a media PC for Blu-ray and HD-DVD playback, and shown how a graphics card with suitable hardware acceleration is a crucial part of the equation.

The video encoding formats used by HD-DVD and Blu-ray require considerable processing muscle to decode, and even the latest Core 2 Duo would fail to cope without some help. So in the same way that Mpeg2 acceleration was built in to graphics chipsets to help with DVD decoding, today’s cards now have acceleration for the tough H.264 AVC format commonly used on HD-DVD and Blu-ray titles.

Both ATI and Nvidia have supported H.264 acceleration on their chipsets for some time: you’ll need an ATI Radeon X1600 or above, or an Nvidia Geforce 6600 GT or above. The question, though, is which graphics company does it better?

More specifically for media PC owners, which company does it better given the additional constraints and requirements of a media PC system? If you’re happy to accommodate a hefty full-height card with a potentially noisy fan, then go ahead and fit any model you like. But if you need a low-profile card that runs quietly and supports HDMI connectivity (with HDCP), then your options are drastically reduced.

Indeed, at the time of writing, we could find only two cards that completely fitted the bill: the Sapphire X1600 Pro HDMI, which uses an ATI Radeon X1600 chipset, and the MSI NX7300GS-MD256EH, which has an Nvidia Geforce 7300 GS chipset.

While the chipsets in each are not of equal standing, the cards still represent the only choices for anyone who wants a low-profile card (to squeeze into a slim case) that supports H.264 acceleration and has an HDCP-compliant HDMI port. So in this month’s Hands On Hardware we’ll compare their features, performance and suitability in a media PC.

A brief tour
The Sapphire and MSI models on test are PCI Express x16 cards, supplied with blanking plates for full-height or low-profile cases. Their core graphics processors are clocked at 500MHz and 550MHz respectively. Both cards are equipped with 256MB of memory, although the Radeon X1600 and Geforce 7300 GS have 128-bit and 64-bit memory interfaces respectively.

The MSI card is passively cooled by a heatsink alone, while the Sapphire card uses a small fan. This fan is fairly quiet in operation, although it’s noisier than the MSI card, which runs in silence.

Both cards are equipped with HDCP-compliant HDMI ports, which provide a protected digital connection to a suitable consumer display without the need for adapters. The DVI interface more commonly found on PC graphics cards is 100 per cent compatible with HDMI and uses the same signals for video, so adapters can be used for TVs with HDMI only.