Is overclocking limiting power draw or GHz?

Cidona

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Apr 17, 2015
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Dear Forum.
When one overclocks CPUs, are they doing so (in layman’s terms here), by limiting the maximum allowed power draw or is it setting a limit on the max allowable GHz.
If it is by limiting the power draw, and what you were working on is primarily single threaded on a given day, it would seem that you would still be able go (say for example only) to 4.8GHz. However, if you were working on something heavily threaded the next day that it would only go (again for example only) 3.8GHz. (or whatever it could get at the same set power draw as the single threaded @ 4.8GHz).
If overclocking is done via limiting GHz then it would seem you have to limited your overclock to the worst situation (in the example above, the 3.8GHz). This would be less desirable as it would seem you would have to limit your single threaded clock to the same 3.8GHz (or whatever the real-world clocks would allow depending on CPU, cooling, etc.).
I know this is over simplification at the greatest level :) ,Thank you for any insight you can provide in this regard.
 
Solution


No not on an unlocked CPU that has been overclocked. The speed is the same whether it is single-threaded or multi-threaded.

If you are using a locked CPU it will have a turbo boost speed higher for single-threaded and a lower boost speed for multi-threaded workloads.


Thank you very much for your reply volkgren! So do you end up getting different maximum clock speeds for workloads that are primarily single threaded versus what you get for maximum clock speeds with a more multi threaded workload?
 


No not on an unlocked CPU that has been overclocked. The speed is the same whether it is single-threaded or multi-threaded.

If you are using a locked CPU it will have a turbo boost speed higher for single-threaded and a lower boost speed for multi-threaded workloads.
 
Solution



Ah, I guess that's the rub. :) Pity, I would have thought there was a way to let it run as high as it can to a certain power draw limit or something to allow the best of both worlds.

Thanks again for your answer!!
 
There is what I call an overclocking triangle of cooling, Voltage, and GHz.
If you increase Voltage 20% and GHZ 20% then you will need 44% more cooling for the same temperature 1.2X1.2=1.44
So it makes sense to start with good cooling, then increase the Voltage to support your speed increase, then increase the speed and test for stability.
At some point you will exceed your cooling, or run into a Voltage limitation that limits your overclocking.
With multiplier overclocking it's just about that simple. With FSB overclocking RAM speed, PCI bus speed and many other factors can limit the results, or enhance them.
 


Thanks for the response william p. I guess it's the nature of the beast with the multipliers, etc. that at the end of the day you are still stuck with setting the top GHz based on whatever your cooling allow for on the multiple core workload rather than having a 'dynamic' maximum GHz that will be higher if you are just using a few cores.

What I was really hoping was feasible with overclocking was something like the Turbo Boost Feature, but with bumped up (overclocked) GHz by using good cooling.
 
In the Throttlestop/Unlocked CPU method there is the option to overclock only 2 cores of a 4 core CPU. This could give a big boost for single thread apps. But Voltage will be raised on all cores. TS works in Windows and a profile can be saved to be turned on and off as needed. it was designed to undervolt, and underclock laptops but with an Unlocked CPU it can overclock as well. the Dell E520 in my sig. was done that way.
 


Thanks again for the additional insight william. I can see how that might be useful for genuine 'tweakers' :), however I was hoping for something a bit more seamless that needing to switch profiles, etc.

It was more for for my education rather than an immediate purchase/problem or such. I'm considering switching software next year and in certain areas it is multi threaded (though majority of workload would be single threaded). Figuring I'll be making a purchase soon after the switch. Since I only get time to check out tech stuff here and there I have to take the slow boil approach and try figure things out of a longer period, etc. Maybe the next gen i9s will have 'super turbo' that will satisfy my desires and be equal to 4 core with low core workloads and still be able to have the benefit of multi cores when needed. :).

Thanks again!