what speed does a reduced processor run at?

Discussion in 'Mac Basics and Help' started by luminosity, May 22, 2006.

  1. luminosity macrumors 65816

    luminosity

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    Jan 10, 2006
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    Arizona
    #1
    If i have my 1.33 Ghz processor running at reduced speed in my iBook, what speed is it running at?
     
  2. Benjamindaines macrumors 68030

    Benjamindaines

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    Mar 24, 2005
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    A religiously oppressed state
    #2
    I've asked this many times and have never found anything anywhere to tell me, so what I think is.... that the processor still runs at 1.33GHz it just gets less power. If this makes any sense please let me know!
     
  3. matticus008 macrumors 68040

    matticus008

    Joined:
    Jan 16, 2005
    Location:
    Bay Area, CA
    #3
    Getting exact figures is very difficult for PowerPC processors, but the speed is generally reduced to somewhere in the 700-800MHz ballpark on most "low power" modes for CPUs, and I'd assume that it would be somewhere in this range.

    Edit: 1.33GHz G4 runs at 766MHz according to my developer notes.
     
  4. luminosity thread starter macrumors 65816

    luminosity

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    Jan 10, 2006
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    Arizona
  5. matticus008 macrumors 68040

    matticus008

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    #5
    No problem :).
     
  6. FF_productions macrumors 68030

    FF_productions

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    Mt. Prospect, Illinois
    #6
    Pretty much answered the question...

    Yeah, when it's running at REDUCED, your processor will run at half the speed: 1.8 ghz->900 mhz.
     
  7. matticus008 macrumors 68040

    matticus008

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    Location:
    Bay Area, CA
    #7
    Well, the G5s and last-revision G4s can run at half or quarter speed. Earlier processors used a slightly different speed-stepping mechanism that wasn't directly calculable.

    I'm just saying this for anyone who uses the search feature and finds this thread later on.
     
  8. yellow Moderator emeritus

    yellow

    Joined:
    Oct 21, 2003
    Location:
    Portland, OR
    #8
    You could always give:

    sysctl -a hw.cpufrequency

    A shot and see what you get.
     
  9. luminosity thread starter macrumors 65816

    luminosity

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    Jan 10, 2006
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    Arizona
    #9
    it gave me 1.3333333

    So, I'm not sure what that means in this case.
     
  10. yg17 macrumors G5

    yg17

    Joined:
    Aug 1, 2004
    Location:
    St. Louis, MO
    #10
    It gave me: 1800000000

    So either my computer is really, really, really fast, or it's giving me the number in a really small unit that needs to be coverted to GHz. :D
     
  11. matticus008 macrumors 68040

    matticus008

    Joined:
    Jan 16, 2005
    Location:
    Bay Area, CA
    #11
    It gives you the speed in Hz. It's also not terribly accurate, especially on 12" 867MHz PowerBooks, for some reason. On all of my computers, it's always only reported the stock speed.
     
  12. zen.state macrumors 68020

    zen.state

    Joined:
    Mar 13, 2005
    #12
    yes. this sosrta thing started around when the 12" powerbook first came out I think. the 867 12" ran at 500 in battery save mode or whatever. 766 sounds right for a 1.33.
     
  13. yellow Moderator emeritus

    yellow

    Joined:
    Oct 21, 2003
    Location:
    Portland, OR
    #13
    There have been tons of inacccuracies reported from that sysctl command since day one. It shouldn't be relied upon on PPC architecture. For exacmple, I'm on a "reduced power setting" on my laptop right now, but it still reports the "correct" (normal) CPU speed:

    yellow% sysctl -a hw.cpufrequency
    hw.cpufrequency: 1249999995

    Some older model of Macs running Panther would report sub-rated CPU speeds consistantly, causing people to get uppity. But those were red herring as well. I didn't know the accuracy for this had changed for G5s or for MacTels. Try using:

    sysctl -a hw

    For a more detailed look at what it will spit out at you.
     

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