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Comment by BeeOnRope | Hacker News Reader

I'm this case the frequencies are similar and so wall clock time reflects the IPC difference (also, the two CPUs take the same code path, so the I is the same in this case, which isn't always true).

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But on these processors, I believe the frequency is rarely sustained right? Due to thermal throttling and other factors.

That only really happens on laptops, which can't dissipate as much heat as desktop systems due to size constraints. On a desktop, if you're using even AMD's stock cooler, you won't thermal throttle. That is, if you don't overclock.

It's not about throttling. What will happen is that the CPU won't automatically clock up dynamically as much if you have worse cooling.

They behave like GPUs more and more with regards to clocks.

That's the same thing. Intel calls their stuff a dynamic boost so that some of their measurements like TDW are for lower clocks. Both CPUs end up scaling their clocks to a wide range.

>They behave like GPUs more and more with regards to clocks.

I think it's the other way around? CPUs had "boost" before GPUs.

Modern processors with boost configurations are rather complicated about "thermally throttling". These days with AMD's stock coolers you will be able to at least get the sticker speed on the CPU even at 100% load for a sustained time. Chances are, you'll actually get some % more speed than the sticker as it will usually continue to boost as long as power delivery and temperatures are stable. So even with an entirely stock configuration, a better motherboard and cooling system will overall net you more performance. This is without doing any traditional "overclocking" and just going with the settings designated with the CPU and motherboard. This same idea also applies to most of Intel's parts as well.

Could be that one process spends much less time sleeping for IO thus still having the same wall clock time.

In this case, there's probably only memory IO which (afaik) cannot put a process to sleep.

There is no IO, and it is not memory intensive.

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