Another important announcement on this morning keynote was the confirmation that Intel will deliver quad-core CPUs next year. With that, Rattner decided to explain why multi-core technology is better than just raising the CPU clock.

The chart in Figure 5 is quite interesting. If you overclock your CPU by 20%, the performance won’t increase 20% (since the overall performance of a computer doesn’t depend only on the CPU) and power consumption will increase a lot (73%). However, if you underclock your CPU by 20%, the power consumption will drop a lot (50%), while the performance won’t drop that much (87% of the original performance).

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Figure 5: Overclocking and underclocking effects on performance and power.

So, if you get two ”underclocked“ CPUs and build them dual-core, the power consumption will be equivalent of a single-core CPU running at its full clock rate, however the performance leap will be impressive (73% greater, according to Intel), achieving the same performance level of an overclocked CPU but consuming far less.

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Figure 6: The dual-core approach.