Core 2 Duo Vs. Core Duo: Merom and Yonah square off

Intel has consistently impressed with its mobile CPUs. The ageing Pentium M processor continues to be a solid foundation for laptops or desktop PCs (like the one in our ultimate quiet PC feature). The successor to the M processor -- the Core Duo (codenamed Yonah), is a marvel of engineering that helped push the Centrino brand to new heights.

But what of the recently released Core 2 Duo range of processors, known in tech circles as 'Merom'? Intel says they are up to 20 per cent faster than the current crop of mobile chips, but are they really as good as it makes out? Bored, disillusioned with the world and with a complete lack of anything better to do, we thought we'd break it down for you Crave readers.

The first thing you need to know about Core 2 Duo is that it's not hugely different to the Core Duo. The key difference is that the fastest chips in the range, the T7xxx series, use 4MB of level 2 cache instead of the standard 2MB. The entry-level chips use 2MB, but all Core 2 Duo CPUs have the benefit of 64-bit EM64T support -- though we won't see the full benefit of this until Windows Vista rolls around.

For our test, we got hold of three laptops, two of which were from rockdirect. The first rock laptop uses a 2.33GHz Intel T2600 CPU -- the fastest in the Core Duo range -- while the second uses the new 2.13GHz T7400 from the Core 2 Duo family. The third laptop is a non-retail reference sample boasting a T7600 Core 2 Duo CPU. All three laptops use identical Intel 945PM chipsets, 1GB of DDR2 533MHz memory, and an Nvidia GeForce Go 7900 GTX graphics card.

To put them through their paces we ran the PCMark 2005 synthetic benchmark application to test their core performance ability. We also ran 3DMark 2005 to test graphics capabilities, and MobileMark 2005 to test features such as battery life and general mobile performance. We also tried out Cinebench 9.5, a free 3D rendering benchmarking tool, to put the systems through their paces.

According to PCMark 2005, there isn't a massive difference between the three processors. The Core 2 Duo was around 5 per cent quicker, which isn't worth writing home about. Cinebench 9.5 showed more of a difference -- the top-spec Core 2 Duo machine was 11 per cent faster than the Core Duo system in our single CPU test, and 8.5 per cent faster in the multi-CPU test.

Unsurprisingly, we didn't spot much difference between the three processors during 3D gaming tests. They returned a nearly identical score in 3DMark 2005 and pretty much the same frame rates in F.E.A.R. As expected, the major bottleneck here is the graphics card. The Core 2 Duo processor is likely to be better than the Core Duo at running CPU-intensive games (such as those that display large numbers of non-playable characters on a screen simultaneously), but in most gaming situations the two CPUs are very similar.

The all-important battery life figures make for interesting reading. All three laptops lasted pretty much the same amount of time when playing a DVD movie and they ran out of juice within a couple of minutes of each other when browsing the Web using Wi-Fi. We can only conclude that this is a good thing, as the Core 2 Duo gives better performance without losing any battery life.

Ultimately, we have to conclude that the performance delta between Core Duo and Core 2 Duo is relatively small in most cases, but there are noticeable differences when running CPU-intensive applications. When using your laptop for simple everyday tasks like writing Word documents you'll notice zero advantage with a Core 2 Duo. However, the new CPUs come into their own when performing more demanding tasks such as 3D rendering. Here it outperforms its predecessor by a notable, if hardly mind-blowing margin.

You can check out the full review of the rockdirect CTX T7400 here. -Rory Reid