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This is not a production question, just something that I've been thinking about.

When speccing out CPUs I know the general rule is a faster clock speed will make a core run faster and the greater number of cores you have the more you can do in parallel. However what makes a "newer" CPU generally faster than an older CPU other than these two things?

For example:

  • There is a noticeable difference between an older i5 and a newer i5 despite having the same number of cores and around the same GHz.

  • My current dual core i5 running at 2.5 (I believe) GHz would surely blow a Pentium 4 out of the water, despite the Pentium running at > 3GHz. I'm sure I could blow a dual core server from 2004 out of the water as well just to make things fair core-wise. I have never done any formal benchmarking, these are just educated guesses.

What are some things to look for when speccing out CPUs?

Kevin Panko
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1 Answers1

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Architecture.

A CPU at 3.0Ghz means that the CPU is doing 3 billion somethings per second. As computer architectures grow more efficient, they are able to do more with each clock cycle (the something).

I haven't kept entirely up to date, but back when the Pentiums 4's were hot stuff, the reason comparable AMD processors had a lower clock rate was because they did more per clock cycle than the P4. The trade off is a clock cycle on an AMD processor took longer.

Some processors can execute multiple instructions in a single clock cycle. Some processors take multiple clock cycles to execute a single instruction. Many processors uses a technique called pipelining, which allows them to have instructions that take multiple clock cycles to execute, but still manage to execute roughly 1 instruction per clock cycle.

Darth Android
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