I would like to buy a new laptop, and this issue appeared:
If there is a notebook with 1.4 ghz proc, and there is an another with 2.6 ghz from the same serial, how this parameters related to the battery draining.
I mean if I use the #1 for general purpose, and the #2 for general purpose, is there a countable battery draining time?

  • I can only guess that you are comparing base clock frequencies here. These are not enough to make any assumptions about battery life. The exact CPU models would be a step up in the quality of information presented. Better yet, add in the model names of the laptops you are interested in. Without this information, nobody can judge battery life of two laptops you want to compare. – user13807 Feb 21 '20 at 15:00
  • If we assume both CPUs are the same brand and generation, then typically the CPU with the higher clock speed also has a higher TDP. That means it can drain the battery quicker, but that depends on your power & performance settings. Modern CPUs can scale their actual clock speed to a more efficient level for a given workload. So both CPUs may drain the battery similarly since the "faster" one could downclock for a light workload. However, the battery drain is majorly affected by other components in a laptop, so two different laptops with similar CPUs will have different battery life. – Romen Feb 21 '20 at 15:15
  • the #1 is the base 13' mac: 1.4GHz quad-core 8th-generation Intel Core i5 processor And the second one is also 13' mac: Intel® Core™ i5-8269U Prozessor (6 MB Cache, bis zu 4.20 GHz) – Peter Feb 21 '20 at 15:31
  • Not to go from low level to high level, but most laptops will have an estimated battery life (in hours) listed in their spec sheets. This estimation is typically the longest possible time they were able to achieve on a full battery charge. This test can differ manufacturer to manufacturer, but it is typically done with minimal services running, idle on the desktop, in order to achieve the highest possible time for them to advertise. Adding additional load will always reduce that number. – Evan Feb 21 '20 at 19:22

The TDP of an i5-8269U is 28 watt.

TDP = thermal design power = most power cpu will draw when running @ 100% = one of the best ways to gauge a CPU's impact regarding power draw.


if I use... for general purpose... is there a countable battery draining time?

probably not.

General purpose use will rarely get cpu usage high; would kind of have to define what you mean by "general purpose use".

The i5-8269 is an 8th-generation Intel Core i5. You mention the #1 is the base 13' mac: 1.4GHz quad-core 8th-generation Intel Core i5 processor but do not specify the CPU model number. In any case if both CPU's are an 8-gen cpu then for general purpose use those CPU's are likely not run anywhere 100% thus they will typically down clock in frequency to save power. This is known as frequency scaling or cpu throttling.

as I type this, the i7-6700k in my win10 desktop pc is a 4ghz cpu having TDP of 91 watt, but is currently only running at 0.8 ghz per CoreTemp, thus drawing very little power. Basically every late model cpu will operate this way, such that you shouldn't worry about power draw based on cpu for general purpose use. But if you game or crunch numbers then the cpu would draw extra power and reduce laptop battery life.

If you have to choose between two cpu's, both being 8th-generation Intel Core i5, then choose the one having the highest base clock frequency. That will provide better performance whenever needed, which should be rarely because you said "general purpose use". Laptop cpu's are very good now at power management and it would be incorrect to assume or infer that a higher frequency cpu will always draw more power.

  • Not trying to nitpick, but CPU throttling is a different story entirely: dropping below base clock during load, due to thermal or power constraints. – user13807 Feb 21 '20 at 17:35
  • I think it depends on the context refering to "throttling". There's throttling based on TDP and the cpu overheating, and there's intel speedstep which throttles the cpu dynamically based on cpu core voltage and operating frequency. different story yes, but kind of in the same book. – ron Feb 21 '20 at 17:45
  • This answer doesn't point out something that can be much more important for determining "battery draining time": The other components in the computer (GPU, HDD vs SSD, fan vs fanless, screen, speakers, WiFi) may draw more power on one model vs the other. Even if both CPUs are the same gen and scale to the same clock speed, the total power draw of the laptop can still be very different. I'm not familiar with the Mac models they mentioned, but the components I listed above are worth noting for their impact on battery life. – Romen Feb 23 '20 at 5:07
  • I think it's also important to note that a large frequency difference might mean a ULV binned part. At same load and frequency, a U series Intel CPU may well draw less power than an M or H series, and a Y series even less than that. A higher boost frequency might also be more important than base frequency depending on workload and whether boost actually happens often enough (which would depend on cTDP). – timuzhti Feb 28 '20 at 14:20

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