But a deep pipe allows for many people to each do one thing, and can help with a design. Instruction size - some processors deal with larger amounts of data in the same time. For example, dealing with 64 bits at a time is faster than 32 bits if you want to move the same amount of data from one place to another. This is a reason that newly written apps can be faster than older apps on the same processor. Instruction set efficiency.
Some descriptions are more efficient in the real world than others.
Primarily the newer the design, the more efficient the processor is. See RISC vs CISC for more on this. Conclusion Processor speed is a pretty complex issue - it is not just MHz. So don't be trapped into thinking that CPU is everything - it isn't, it is one part of a larger picture. But if you care about CPU speed, then PPC's and PowerMacs blow the competition away.