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Clock Speed Calculation in Multicore Processors
If I see a CPU that says "2GHz quad core" on the box, does this mean that each of the four cores are running at 500MHz? If so, why are four 500MHz cores faster than one core at 4x the clock speed?
No, it means 4 cores are each running at 2Ghz. Also be aware that each hertz doesn't mean what it used to. Some processors are able to get much more from each cycle than others, which is why you would still greatly prefer a 2Ghz Core 2 Duo to a 3.4Ghz Pentium D, even though the Pentium D also has two 64bit processor cores and each runs at 3.4Ghz (with hyper-threading, at that).
Additionally, most tasks don't scale well to multiple cores. This is why you need to think of 4 2Ghz cores rather than one processor running at an 8Ghz-equivalence. Most of the time you're focusing on one thing that is only able to use one core, with maybe a few simple background tasks using some time on the other cores. Notable exceptions include "serious" gaming and heavy audio, video, or image editing/encoding/decoding.
