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Battery Life Scenario

Discussion in 'Android Devices' started by Larry_ThaGr81, May 20, 2010.

  1. Larry_ThaGr81

    Larry_ThaGr81 Member
    Thread Starter

    Which kernel would offer you the best battery life?

    Everything on all four phones are the same with the exception of the kernels they are running. Choice of phone isn't important because the same kind of phone is used for each scenario below.

    Phone one has the bekit stock voltage 600MHz kernel clocked to 600MHz.

    Phone two has the bekit low voltage 800MHz kernel clocked to 600MHz.

    Phone three has the bekit low voltage 1000MHz kernel clocked to 600MHz assuming that frequency is a option with SetCpu.

    Phone four has the bekit increased voltage 1100Mhz kernel clocked to 600MHz assuming that frequency is a option with SetCpu.

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  2. ska.t73

    ska.t73 Android Expert

    Why would you be running a kernel clocked up to 800MHz and 1000MHz if you just plan on running it at 600MHz all the time?
  3. UBRocked

    UBRocked VZW Nexus Please!!!

    Maybe this would be better if you added a poll??? It would be like polling the audience on Who Wants To Be A Millionaire :D

    All joking aside...what are you trying to figure out here? If you run a kernel @ 600MHz...it will offer the same battery life regardless of the what the top end and unused frequencies might be.
  4. Fadelight

    Fadelight Android Expert

    Not necessarily. You mustn't forget about the stepping. I can't be bothered to look up the steppings since I am feeling insanely lazy right now, so I am just going to make some shit up, but this is just for arguments sake anyway.

    Say you have a 600mhz 5 slot LV. The steppings are 125mhz, 250mhz, 400mhz, 500mhz, and 550mhz.

    You have an 800mhz 5 slot LV. The steppings are 250mhz, 400mhz, 500mhz, 600mhz, and800mhz.

    You have a 1ghz 5 slot LV. The steppings are 250mhz, 500mhz, 600mhz, 800mhz, and 1ghz.

    Your CPU runs "on demand" which means it is constantly fluctuating between the various steps. (It switches in steps, not constantly variable.)

    This means that when comparing the 1ghz to 600mhz, if 50% of the CPU is needed, one will be running at 250mhz while the other is running at 500. Another step up? 400mhz vs 600mhz. One has a sleep speed of 250mhz while the other has 125mhz. That means the 600mhz kernel will always be running at half the speed of the 1ghz.

    If you were to set the 1ghz CPU to run at 600 all the time, that means that rather than allowing the CPU to choose from 5 slots as needed, it can now only run in 3 positions. Low, Medium, and high.

    With that in mind, my answer is this:

    If you want a kernel that will only run at 600mhz, choose a 600mhz kernel. Anything more is just wasting a slot that would be very well used otherwise.

    LV kernels will almost always run cooler and use less battery than standard voltage kernels of the same speed. (I say almost because it would be just my luck the OP has the "freak" phone that melts down with an LV kernel.)

    Last but not least, remember... when you are running overclocked, your phone is still running "on demand". If you aren't using it, it will be set to the lowest step setting available. (Usually 250mhz. Same as stock.) You'll only notice the battery drain if you are using an app that requires 100% CPU usage.
    Larry_ThaGr81 likes this.
  5. Larry_ThaGr81

    Larry_ThaGr81 Member
    Thread Starter

    Ok let me ask it like this, clock speed frequencies aside (being set the same). Which kernel will offer the best battery life between SV, LV and IV?
  6. OMJ

    OMJ Bazinga

    That depends entirely on your droid. Some droids like LV some like SV and some like IV. You gotta test them out and find what works for your droid.
  7. Larry_ThaGr81

    Larry_ThaGr81 Member
    Thread Starter

    Hypothetically speaking, which one would offer the best battery life? Phone 1, 2, 3, or 4 from the original scenario.

    I only use the 600MHz kernel, because my test have proven that my battery life is substantially better with the stock voltage kernel vs the low voltage. After my initial rooting, I ran low voltage kernels for about 2 weeks before I discovered bekit offered a stock voltage kernel.

    But maybe others have seen different results.

    Moto Droid
    BBv1.0 bekit stock 600MHz
  8. Larry_ThaGr81

    Larry_ThaGr81 Member
    Thread Starter

    Is SV higher or lower that LV?
  9. OMJ

    OMJ Bazinga

    Standard voltage is higher than low voltage
  10. UBRocked

    UBRocked VZW Nexus Please!!!

    Honestly, I don't think it will matter much with the kernel running at 600MHz. The Low and Intermediate voltages are used to control heat more than anything else. If there would be a difference, I would have to assume that the lower voltages would have a slightly better battery life but again, I doubt that you will notice it at 600MHz.

    Fadelight...The OP didn't mention anything about any kind of underclocking. I was assuming he meant that if you are running 600MHz flat out (not 250MHz minimum and 600MHz maximum). In that case, it wouldn't matter what the steps are. But how many steps could your phone really use between 250MHz and 600Mhz. I seriously doubt that the phone would run at say...400MHz for any reasonable length of time. It would either be idle at 250MHz or maxed out at 600MHz at the first screen swipe. The steps are much more important for setting up profiles than they are for actual use. Having more steps provides users with more options for profiles like charging, standby, failsafe, or to conserve battery life when the phone is low on battery.

    I have no data to back up my statements so I could be wrong but if you looked at a trend of the processor clock speed over the course of the day, what percentage of the timeline would you expect to see for usage in between 250MHz and 600MHz? I would say zero or so close to zero that it would be irrelevant. :)
  11. Fadelight

    Fadelight Android Expert

    The clock on the stock kernel spans from 250mhz to 600mhz, so it would be a safe assumption the OP would run it likewise.

    The phone really does run in incrimental steps for significant lengths of time depending on what you are doing. For example, my CPU sits at about 500mhz when I am running "mytracks". It sits at 800mhz when streaming Pandora or Slacker. When playing with Home screen widgets it is usually sitting at 400mhz. I run my max setting at 1.2ghz, and the only time I really see it full is when mytracks or google nav are actively loading a map (like when you first start it, or when you are coming out of a no-service area), but once loaded, it throttles back. I also see full speeds when using the browser.

    As I said previously... never underestimate the importance of the stepping. ;)
  12. inssane

    inssane Android Expert

    Look in my sig

Motorola Droid Forum

The Motorola Droid release date was November 2009. Features and Specs include a 3.7" inch screen, 5MP camera, 256GB RAM, processor, and 1400mAh battery.

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