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explay

explay June 29, 2024, 1:31 p.m.

Understanding cpu efficiency in idle states

I'm trying to wrap my head around CPU efficiency, particularly when the system is idle. I've heard that modern CPUs have various power-saving states, but I'm not sure how they work or how effective they are.


A few questions I have:

1. How much power does a CPU typically consume when idle?

2. Are there significant differences between desktop and laptop CPUs in terms of idle efficiency?

3. Do additional cores impact idle power consumption significantly?


Any insights or explanations would be greatly appreciated. Thanks in advance!

dfk

dfk June 29, 2024, 10:33 p.m.

Great question! Modern CPUs have come a long way in terms of power efficiency. When idle, they can enter various C-states (power-saving states) that significantly reduce power consumption. The exact consumption varies, but it can be as low as a few watts for desktop CPUs and even less for mobile ones.

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Dawen

Dawen June 30, 2024, 12:04 p.m.

is right about C-states. It's pretty fascinating stuff! The CPU can shut down parts of itself that aren't being used, like cache or even entire cores. The deeper the C-state, the more power saved, but also the longer it takes to "wake up" when needed.

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Mr. Ray

Mr. Ray June 30, 2024, 6:35 p.m.

Don't forget about P-states! While C-states are about shutting things down, P-states adjust voltage and frequency on-the-fly. It's like a car engine that can instantly switch between being a fuel-efficient 4-cylinder and a powerful V8 as needed.

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wr325

wr325 July 1, 2024, 11:15 a.m.

To answer your second question, laptop CPUs are generally designed with power efficiency as a top priority, so they often have more sophisticated power-saving features. Desktop CPUs have been catching up, though!

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CR7

CR7 July 2, 2024, 1:55 p.m.

Guys, are we really geeking out about CPUs doing nothing? xD чВ Next, we'll be discussing the aerodynamics of stationary cars!

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anderson1992

anderson1992 July 2, 2024, 10:36 p.m.

Hey, efficiency matters! It's like... uh... a really efficient couch potato. They excel at doing nothing! xDD But seriously, this stuff is crucial for battery life in laptops and overall energy consumption in data centers.

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dhdfgfdcgh

dhdfgfdcgh July 3, 2024, 8:11 p.m.

To add to what others have said, the number of cores does impact idle power consumption, but not linearly. Thanks to good power gating, extra cores can be almost completely shut down when not in use.

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gfdj

gfdj July 5, 2024, 2:38 a.m.

If you want to dive deeper into this topic, I'd recommend checking out the white papers on the Advanced Configuration and Power Interface (ACPI) website at uefi.org/acpi. They have comprehensive technical documentation on power states and efficiency mechanisms in modern processors. It's pretty dense reading, but it's the go-to resource for understanding how CPUs manage power at a low level.

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Decline

Decline July 5, 2024, 4:41 p.m.

Thanks for the resource! @explay, just be warned - once you start down the CPU efficiency rabbit hole, you might find yourself obsessively monitoring your system's power consumption. Ask me how I know... )))

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610710

610710 July 7, 2024, noon

All this talk about efficiency reminds me: has anyone tried overclocking their coffee maker for that extra morning boost? No? Just me? Okay then... 

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