By David Johnston
Contributing Writer, RealTechNews

CPU speeds have gotten a lot more complicated than they used to be. In addition to just clock speed, there’s also cache size, and the speed of the FSB that are frequently varied–even within the same brand name of CPU. To help consumers (or so they say) with their confusion over these additional variables, both Intel and AMD have started to use model numbers on their processor instead of just the clock speed.

For example, there are two different kinds of Athlon XP 3000+. What’s the difference? Clock speed and FSB. That’s not nearly the worst example, however. Take the Athlon 64 3200+. There are not one, not two, not three, but *four* different variations of the same processor, not even counting the mobile variant. These differences include clock speed, cache, process (the size of the transistors), and even the socket that they fit into.

Intel meanwhile, has gone with a naming system that is even more obtuse than AMD’s (in my opinion) by using a BMW-like three number scheme to rate its CPU’s speed. So how fast is that Pentium 4 515 and how does it stack up against the 520…or the 520J? Well, the Tech Report has answered all of your questions with a spy-like “CPU Decoder Ring”. This little table which can be sorted on any of the criteria it covers will tell you all of the information you wish you knew about your processor’s clock speed, FSB, cache, socket, voltage, and more. Take a look here.

UPDATE: for AMD processors specifically, AMD has set up its own information page which you can find here.

Intel has added similar functionality to its own site both here and here.