800MHz running 533MHz?

Discussion in 'Macintosh Computers' started by BenForshey, Sep 2, 2003.

  1. BenForshey macrumors newbie

    Joined:
    Sep 2, 2003
    #1
    Hi, I'm really stuck on this one. I read one of the archived posts (http://forums.macrumors.com/archive/topic/25114-1.html) written by "grabberslasher", and followed the instructions in it (on software overclocking your bus speed from 100MHz to 133MHz). It worked! But now my 800 Mhz GigaDesigns upgrade is running at 533 (so says Apple's Profiler), when the jumpers on my upgrade card are set for 1.06GHz.

    I switched the jumpers to an 800MHz setting, and Profiler says I am still running 533 on those jumper settings. I then moved the jumpers to an 800MHz setting, and tested both settings with Cinebench '03. The 533MHz/1.06Ghz setting gives me about 760Mhz of speed (better than before the software overclock--I was getting 740Mhz). On the 533MHz/800Mhz setting, I clock 540MHz of speed.

    The computer is a Gigabit/Ethernet model, and I may be using PC100 RAM, though I'm not sure, because I bought it for an Apple (no speed specified), not as PC100 RAM. I'd love any help...any suggestions... Thanks!
     
  2. gopher macrumors 65816

    Joined:
    Mar 31, 2002
    Location:
    Maryland, USA
    #2
    With built-in 800 Mhz G4, the Macs have to have PC-133 RAM. PC-100 RAM causes many issues for those Macs with 800 Mhz G4s built-in. The case may be the same for G4 upgrade cards. Check with Gigadesigns which RAM they recommend for your machine with the upgrade card.

    http://www.macmaps.com/Macosxspeed.html#RAM

    lists RAM vendors that specialize in Apple RAM and will sell you the correct kind of RAM.
     
  3. BenForshey thread starter macrumors newbie

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    Sep 2, 2003
    #3
    is that why?...

    Thanks for the RAM advice (really!), but is that why I am running 533 instead of 1.06GHz? I really have no idea, but I don't think RAM would do that.
     
  4. OutThere macrumors 603

    OutThere

    Joined:
    Dec 19, 2002
    Location:
    NYC
    #4
    Re: is that why?...


    Your bus speed is only as fast as the slowest link....soooo- with 100mhz ram you cant have a fully 133mhz bus.
     
  5. BenForshey thread starter macrumors newbie

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    Sep 2, 2003
    #5
    so...

    So, that means that I won't have the 133Mhz bus speed. Got it, and thank you. But why the 533MHz processor speed? It is, after all, an 800MHz processor upgrade.

    Another question: I looked up the RAM that I bought, and it is "PC-100 / PC-133 Memory Modules"...so I don't really know if it is PC-100 or PC-133, do I?
     
  6. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #6
    Because bus speed and processor speeds correlate, if you bus speed is only so fast, its only multiplied by 100, not by 133.

    i.e. an 5.3x multiplier on a 100mhz bus = 533mhz
    a 5.3x multiplier on a 133mhz bus = 700mhz

    Now this doesnt show your exact problem, but it works similar to this.
     
  7. BenForshey thread starter macrumors newbie

    Joined:
    Sep 2, 2003
    #7
    okay, but...

    Thanks again for the replies! Okay, here's the deal. It's an 800 Mhz processor upgrade card....so if my RAM is only PC-100, an 8x multiplier (the current jumper setting) should give me 800MHZ, not 533. With my jumper set at 8x, how am I getting 533? Thank you!
     
  8. MacBandit macrumors 604

    MacBandit

    Joined:
    Aug 9, 2002
    Location:
    Springfield, OR (Home of the Simpsons)
    #8
    Re: okay, but...

    Have you considered going to the manufacturer for support?
     
  9. BenForshey thread starter macrumors newbie

    Joined:
    Sep 2, 2003
    #9
    Well...

    Sure, but its not a manufacturer problem. If I turn the software overclocking off, the profiler registers the upgrade card as 800MHz...but I think I loose the 133MHz bus speed. The funny thing is, even with the upgrade registering as 533MHz, the processor performs as good, if not better than the processor registering as 800MHz. Any help here? Thanks guys!
     
  10. gopher macrumors 65816

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    Mar 31, 2002
    Location:
    Maryland, USA
    #10
    Re: Well...

    Well there is your problem. Overclocking will make processors not always work quite as expected. The ratio of bus to processor frequently gets changed when you overclock and it can cause all sorts of problems. If you want to overclock and do it right, consult the folks at http://www.xlr8yourmac.com/ who have a lot of experience with overclocking. Overclocking will also in most cases void the warranty on your card since they weren't really designed for that. If you wanted a faster upgrade card, you should have waited for one before buying it.
     
  11. MacBandit macrumors 604

    MacBandit

    Joined:
    Aug 9, 2002
    Location:
    Springfield, OR (Home of the Simpsons)
    #11
    Re: Well...

    It sounds to me that the clock speed is just not being reported correctly. This is most likely due to current programs not recognizing this CPU at those multipliers. I wouldn't go by them. I would use some simple benchmark tests to see if you are realizing any benefit and if you are don't worry about what speed is being reported just be happy that you know the cpu is running faster.
     
  12. BenForshey thread starter macrumors newbie

    Joined:
    Sep 2, 2003
    #12
    Thank you!

    Thanks! That's very helpful....I'll see what I can do about getting some PC133 RAM, then software overclock my bus speed. Thanks again!
     

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