How does frequency on a CPU impact performance? I.e. if I overclock a 2Ghz CPU to 4Ghz, is it +100% performance?
In: Technology
No it’s not a linear increase like that.
Personally though I find clock speed to be the best indicator of performance apart from maybe benchmarks. Like others have said, a faster clock speed means that the CPU can process more instructions in less time.
There are other factors though like cache size (the more data you can hold in cache the less fetches you need to make from main memory – and fetches are very costly in terms of performance).
Another factor could be the instruction set being used, essentially you get simple instructions such as ADD which takes the values in 2 different registers, adds them and stores the result in a third register. We’re getting a bit outside my area of expertise now but let’s say the ADD instruction can be completed in a single clock cycle.
Now lets imagine an instruction set which contains a multiply instruction which can complete in 2 clock cycles. And imagine we want to multiply 8×7.
How many ADD instructions does the first simple set need? Maybe 7.
How many MUL instructions does the more complex set need? Let’s say 1.
In these examples, we could say that a CPU with lower clock speed using the more complex instruction set might actually have better performance. To be clear, I’m not arguing that complex instruction sets are inherently superior, only in this made up example I’ve given.
In summary, it’s a balancing act, but for consumers I’d generally state that clock speed is a good indicator of performance.
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