Hands on: Make the most of high-definition

The playback of high-definition video continues to present a challenge for all but the latest PC configurations.

The key to smooth presentation is a quick processor and a graphics chipset with appropriate acceleration.

If your existing system copes with some HD material but struggles with more demanding titles, an upgrade is in order ­ but you may not need to swap both your main processor and graphics card for quicker models.

Last time we measured the impact of swapping the relatively modest ATI X1600-based graphics card in our test entertainment PC with one sporting an Nvidia Geforce 8600 GPU. Like certain ATI Radeon HD 2x00 GPUs, this can offload most of the HD decoding from the main processor.

On our Intel Core Duo T2600-based system, the processor hit fell from 100 per cent with dropped frames on the toughest titles to as little as 25 per cent, with silky smooth playback. This time, we’ll keep our old graphics card but upgrade the main processor to see how it compares.

Test system
Our test system consisted of an Asus N4L VM DH motherboard fitted with a Sapphire X1600PRO HDMI graphics card and 1GB of Crucial DDR-2 memory. The original configuration used an Intel Core Duo T2600 mobile processor clocked at 2.16GHz and, while it coped with most high-definition titles on Blu-ray and HD-DVD, it struggled with others.

The upgrade this time was to an Intel Core 2 Duo T7600 processor clocked at 2.33GHz. It ran fine on the Asus board following an update to the latest 0905 Bios. The T2600 and T7600 use dual cores and run on identical 667MHz buses, but there’s more than just 166MHz of clock speed between them ­ the T7600 employs the sophisticated Merom core rather than the T2600’s Yonah. So what does that get you?

The newer Merom core has almost double the number of transistors, most of which accommodate a doubling of the Level 2 cache from 2 to 4MB. It also has architectural improvements that allow it to access and handle information more quickly. It’s the same as the desktop Core 2 Duo architecture (Conroe) but runs at slower clock speeds and front-side buses (FSBs) to save power.

The good news for owners of existing Core Duo systems is that a Merom processor running on a 667MHz FSB can be swapped in with nothing more than a Bios update. To see what difference this makes we ran Sysmark 2004 with both the T2600 and T7600 at XGA resolution, followed by measuring the processor hit when playing scenes from Casino Royale and X-Men III on Blu-ray at a resolution of 1,920x1,080 pixels.