Champion vs. Rookie: Core 2 Duo vs Core i3

The Core 2 Duo has been the processor of choice in laptops for about three years. Over those three years the average speeds of Core 2 Duo processors have advanced significantly, and many of today's Core 2 Duo laptops have speeds of around 2.2Ghz or faster. Core 2 Duo processors have also been the go-to for many less expensive desktop systems, with speeds reaching over 3Ghz.

However, there is a newcomer which is challenging the Core 2 Duo. This is the Core i3. It is very similar to the Core 2 Duo in many ways. Both are dual-core processors and most Core 2 Duos and Core i3 have similar clock speeds. However, the processors are based on different architectures.

So, which one is better?

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The Core i3 is based off a new architecture called Nehalem. The Nehalem architecture has numerous advantages over the Core 2 architecture. Nehalem is better constructed for quad-core processors, has hyper-threading available, and can use a feature called Turbo Boost which maximizes processor speed. However, because the Core i3 is the low-end Nehalem variant, most of these features are disabled or not relevant - the Core i3 is a dual core processor and Turbo Boost is disabled, but hyper-threading is enabled.

The Core i3 is the slowest variant of the Nehalem based processor. The Core 2 Duo processors, however, don't have the same differentiation between versions of the same architecture. The fastest Core 2 Duo desktop processor has a speed of 3.33Ghz, while the fastest Core i3 desktop processor is clocked at 3.06Ghz.

You might therefor expect that the Core 2 Duo would have the edge - particularly when you consider that the Core 2 Duo costs almost three times as much if you buy it individually - but in fact the Core i3 is faster, and often by no small margin. The Core i3 is faster even in single-threaded applications, but the performance gap really widens in multi-threaded applications. This is because the Core i3 has hyper-threading, which turns the two real cores into four virtual cores. Windows works with the Core i3 as if it is a quad-core processor.

These results remain true in the mobile space, as well. Core i3 processors punch at least 500Mhz above their weight in single-thread applications, and are virtually always faster in multi-threaded applications, no matter the clock speeds of the Core 2 Duo and Core i3 processors you are comparing.

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These differences pan out about how you'd expect them to when it comes to absolute power consumption. The Core i3 processors do consume just slightly more power than Core 2 Duo processors at load and at idle. We're talking a difference of around 10 Watts on desktops and a few on laptops - nothing huge, but a difference none the less.

However, when it comes to power efficiency the answer becomes less clear. In order for a processor to be power efficient, it needs to not only have low power consumption but also the ability to complete tasks quickly. This lowers the overall "task energy" because a faster processor will be done with a task before a slower processor, and once done it will slip back into an idle state.

When viewed from this perspective, the Core i3 is much more efficient than the Core 2 Duo on both the desktop and the laptop. This means that the Core i3 will probably not use any more power than a Core 2 Duo - and may actually use less - unless your usage patterns place a constant load on your processor.

Overall, the answer is clear - the Core i3 is the better processor.

That doesn't mean that it absolutely body-slams the Core 2 Duo. The Core 2 Duo isn't hugely slower. However, the Core 2 Duo is on its way out, and the Core i3 is slightly better in just about every way.

In the desktop space, the ease with which you can find a Core i3 desktop means there is little reason to purchase a Core 2 Duo based system unless you're on a very tight budget. On laptops, however, the story is a bit different. There are still some competent Core 2 Duo systems available, and they're worth considering if their other advantages out-weight the slightly out of date processor.