Hands on: Core Duo reigns supreme

Test results
Clocked normally at 2.16GHz, the Core Duo T2600 system scored 255 in Sysmark 2004 – an impressive increase on the Pentium M 770 system’s 183.

We timed how long it took to encode a 12-minute, 30-second Vob file into the DivX format.

The Core Duo T2600 did it in 14 minutes and 49 seconds, compared with 18 minutes and 46 seconds on the Pentium M 770.

Our Core Duo test rig may have had 2GB of Ram, compared with the 1GB of the Pentium M system, but the increase from 1GB to 2GB doesn’t make a great deal of difference in these benchmarks.

The higher scores measured are almost entirely down to the greater performance of the Core Duo over its predecessor.

Power consumption
Greater performance is one thing, but did it come at the cost of increased power consumption?

To find out, I connected my Maplin power meter to the mains socket running the Core Duo PC and took various measurements.

With Windows running, but the system idle, the Core Duo T2600 test system consumed 56W. This increased to 70W under load, running the DivX encoding process.

In comparison, the Pentium M 770 consumed 54W when idle and 65W under the same load.

These measurements were taken with both systems running Windows with its Power Management scheme set to ‘Always on’.

Both the Pentium M and Core Duo feature Intel’s Enhanced Speedstep Technology (EIST), which can dynamically underclock the processor when idle to conserve further power.

To enable EIST on these processors, you’ll need to change Windows Power Management to ‘Minimal Power Management’ and, if necessary, also enable Speedstep support in the motherboard Bios.

With both systems configured to support EIST, their idle power consumptions fell to 51W for the Pentium M and just 49W for the Core Duo.

To ensure there wasn’t a performance hit with EIST enabled, I re-ran the benchmarks and both the scores and power consumption during testing remained the same as before.

Quick to the Core
Our first batch of results paint a positive picture for Core Duo, which comfortably outperforms the Pentium M, while not consuming more power. New developments, however, mean there are few compelling reasons to build a desktop with it.

Intel’s latest desktop alternative is no longer a power-hungry, heat-generating monster.

The new desktop Core 2 Duo devices are, in essence, mobile processors tweaked for the desktop, running on much lower power and generating less heat than their predecessors.

As such the difference between using a genuine mobile processor such as the Core Duo and one of Intel’s latest desktop chips is much smaller than before.

But that’s not to say Core 2 Duo will kill the concept of Mobile on Desktop.

Most Viiv-compliant motherboards designed specifically for entertainment PCs have been for Core Duo processors, carving the mobile chip a niche which could see it continue to power desktops.

Core Duo facts and figures
Intel’s Core Duo (codenamed Yonah) processor replaces the Pentium M (Dothan), and the biggest difference between them is two cores instead of one.

Core Duo’s Level 2 cache remains at 2MB, but a major architectural difference is that it’s dynamically shared between the two cores.

The Core Duo also supports SSE3 streaming extensions, improving its media performance over the Pentium M although, like the Pentium M before it, there’s no Hyperthreading nor support for 64-bit operating systems.

Core Duo additionally operates on 533MHz or 667MHz quad-pumped front-side buses, in contrast to Pentium Ms, which ran on either 400 or 533MHz buses.

An important physical difference is that while Pentium M and Core Duo both employ 479-pin interfaces, the arrangement has subtly changed, so the new processor won’t fit into old Pentium M motherboards – you’ll need a new model.

The good news, though, is most Core Duo boards should also be able to take the forthcoming Merom mobile Core 2 Duo with only a Bios update – although do check with the motherboard manufacturer first.

At the time of writing, there were nine Core Duo models available from the ultra-low voltage 1.2GHz U2500 to the 2.33GHz T2700. All are produced using a 65nm manufacturing process, and all but the T2300E also support Intel’s Virtualisation Technology.

In terms of pricing you’re looking at about £165 for the 1.83GHz T2400 to about £350 for the 2.16GHz T2600. For more technical information, visit Intel’s website.

Look out for more Core Duo tests in future online articles, along with details on building your own Viiv Media Center PC.