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How can it be, that my current cpu frequency (CPU MHz) for my Intel Core2 Duo T9400M is above max MHz while being on high load? 

➜ lscpu [...] Model name: Intel(R) Core(TM)2 Duo CPU T9400M @ 2.53GHz Stepping: 10 CPU MHz: 2606.581 CPU max MHz: 2534.0000 CPU min MHz: 800.0000 [...]

This isn't limited to lscpu: I get similar values out of /proc/cpuinfo:

➜ bat /proc/cpuinfo [...] model name : Intel(R) Core(TM)2 Duo CPU T9400 @ 2.53GHz cpu MHz : 2635.237 [...]

I found this out while looking over the Node.js documentation and finding, that the current speed value of os.cpus() - even in the example of the documentation - is above the maximum CPU speed according to the model:

[ { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, [...]
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  • bat = cat? Commented Apr 10, 2019 at 21:03
  • 2
    Yes, bat is "a cat clone with wings." github.com/sharkdp/bat Commented Apr 10, 2019 at 21:12
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    less is more, and bat is cat. This is madness!    :-)    ⁠ Commented Apr 10, 2019 at 21:16

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In both cases, your CPU can run slightly faster than its specified frequency, typically when one of its cores is running a CPU-intensive process, and the others aren’t. On your Core 2 Mobile system, this was provided by Intel Dynamic Acceleration; on the Core i7, by Turbo Boost.

The exact details vary from one processor to another. Earlier CPUs could only boost one core, but nowadays multiple cores can be boosted. The CPU ensures it stays within a certain power and thermal envelope.

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