First there was the CPU with a relatively easy way to see its speed - you looked at its clock speed.  Then came advances in CPU magic that meant that the clock speed alone wasn't the determining factor.  Now they've come up with multi-core CPUs that throw this all out the window!

The following description follows in Stephen Hawking's line of thinking - every formula (or tech term) will reduce the readership by 50%.  So I've aimed at keeping technobabble to a minimum to keep readership, and more importantly, reader comprehension at its maximum.

Oh, and just in case you think Intel and AMD are leading the pack, Sun has their four-, six- and eight-core UltraSPARC T1 CPUs shipping (and has done so for quite some time) and have now finished the design and are working on production of their new "Rock" CPU with 16 cores.  Of course, a SPARC core and an Intel core cannot be directly compared - that would make things a little too easy!  :)

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Once upon a time there was a processor called the Intel Pentium III.  It got outdated, so along came the Pentium 4 CPU which was based on the Pentium III, but with "more modern" design ideas.  Things went swimmingly for a while, including adding 64 bit processing to the original Pentium 4 design, but 2 major issues were noted - 1) It ran so hot in a laptop computer that it was impractical for those that don't think blistered thighs is a fashion statement and 2) It wasn't really that fast.

So, Intel had another thunk aboot the Pentium III that was, relatively speaking, a really good CPU.  They decided to implement the now "even more modern" design lessons they learned since designing the Pentium 4 and called it the Pentium M (for "Mobile", or maybe "Much cooler").  It ran at a much slower clock speed, power usage and temperature but added numbers together as quickly as the Pentium 4 did.  "We are onto a good thing here" thought Intel, even though the Pentium M was a 32-bit only CPU core.

As desktop CPU requirements were getting biggerer and biggerer, Intel decided to gaffer tape another Pentium 4 core into the same package, making the Pentium D.  So, the Pentium D is basically 2 * Pentium 4 CPU cores on individual pieces of silicon that will plug into a single motherboard CPU socket.  Old school.  Power hungry.  Damn hot.

Intel also needed to update the Pentium M and did so, making the Intel Core Solo CPU.  They also needed to move to multi-core CPUs, so along came the Intel Core Duo CPU which was 2 * modernized Pentium M cores in the one package.  It, too, was stupidly only 32-bit.  It was basically a stepping stone to a real CPU - the Core 2 Duo - which is a modernized (once again) and full 32/64-bit version of the Core Duo CPU.

Now, Intel has managed to make the Core 2 Duo into a single piece of silicon, so that there's one chunk of silicon in the CPU package, but it has 2 * CPU cores.  Nifty.  Now, they realised that the next step - the Core 2 Quad - can be initially released by gaffer taping 2 of these bits of silicon on the one chip - so the current Core 2 Quad CPUs are basically a pair of Core 2 Duo CPUs in a single package, similar to the Pentium D.  The upcoming Core 2 Quad will be a single piece of silicon containing the 4 * CPU cores.

So, there you go - a basic overview of single and Dual Core Intel P4 (or Xeon) CPUs and how they evolved.  As for AMD, they basically are at the Pentium-D stage right now, with multiple individual cores in a single package, but they are progressing quickly towards multi-core silicon as with the Core 2 Duo CPUs from Intel.

If there's any more technology issues you'd like to see "humanized", please feel free to contact Hilton and ask for some help!