Beige G3 Overclock Stock CPU

Discussion in 'PowerPC Macs' started by comda, Jan 23, 2015.

  1. comda macrumors 6502a

    comda

    Joined:
    Mar 15, 2011
    #1
    Greetings.

    Seems like these Beige old boxes are making a come back these days. I posted here about a month ago about mine. what i want to know is how far and how exactly can i push its stock 233mHZ CPu to? i dont know much about over clocking so the FSB and documents dont make much sense to me.

    http://www.wmld.com/tech/jumperchart2.html

    Can someone please clear this up? i dont understand this chart on that site. According to this site if i have the 233mhz i can go up to the 292 without multiplying the bus speed whatevr that is?
     
  2. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #2
    I'll attempt an answer, since I've been sort of playing with this recently both on beige boxes and on B&Ws, although I've been doing processor swaps more so than overclocking.

    As you might have gathered from your reading, the processor speed is set as some multiple of the bus speed.

    On the beige G3s, the bus speed is 66mhz, and I have been advised not to change this.

    So, this leaves playing with the multiplier.

    At 233mhz, your multiplier is going to be set at 3.5x. Most sources I've read advise-with the same CPU-not going any more than .5x higher than the stock speed, although you can occasionally push this to 1x higher. This means that you could set the multiplier to 4x safely, and end up with a 266mhz system, or possibly go to 4.5x and get ~300mhz. You will have to experiment and see if it's stable with either of these.

    One of my beige G3s is currently running at 400mhz(6x), although I'm using a 400mhz G3 out of a B&W.

    As you've probably also encountered, this is done by changing jumpers on the logic board. There is a small, one piece jumper block under a "warranty void if removed" sticker on the logic board. On B&Ws, this is right next to the CPU, while on beiges it's over next to the PCI slots. These blocks are color coded and have all the correct jumper settings for the CPU frequency that the computer shipped with.

    You need to remove the block, and then use individual jumpers to set things as you want to. There are 9 pairs of jumpers on the beige logic board. These are numbered 1 through 9. If have the front of the computer(optical drive, etc) facing you, 1 is the closest to you, and 9 the furthest away.

    Jumpers 5-9 should not be changed from their stock configuration. This means that you should have jumpers on #5,6,7, and no jumpers on 8 and 9.

    To up your processor to 266 mhz, you need to jumper #2 and #4. To go to 300mhz, you need to jumper on #1.

    I should also add that you need 2mm "micro" jumpers and not the standard 2.5mm hard drive jumpers. I bought 100 of them here

    http://www.ebay.com/itm/350557475053?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT

    (For the mods-no connection with seller other than a happy customer).

    The last thing is that by increasing the speed, you will also end up with a hotter running CPU. If you have the G3 "outrigger"(desktop) there's really not a good way to get a fan on the CPU. I'm still experimenting with good ways to get airflow over it. If you are fortunate enough to have a desktop, you should be able to stick a thin fan directly on top of the heatsink(as I did with my B&W G4 upgrade).

    Finally, have fun! I don't know a whole lot, but this is something that I'm educating myself about and "learning while doing."
     
  3. desantii macrumors 6502

    desantii

    Joined:
    Sep 9, 2006
    Location:
    Aurora, IL
    #3
    I also have a 400mhz G3 and it runs well at 466mhz in my tower beige G3
     
  4. comda thread starter macrumors 6502a

    comda

    Joined:
    Mar 15, 2011
    #4
    Alright. Is there a reason i shouldnt touch the "bus speed." and dumb question. is that located on the same pins as the jumper settings im already after? i know the jumpers im already after are right beside the PRAM battery and yes i have the outrigger, or gossamer. the desktop model.

    Looking at the chart http://www.wmld.com/tech/jumperchart2.html

    If i do take it 4.5 i can get it up to 300MHz on that Stock CPU from a lousy 233mhz. But what is the Front side bus? im not all too familiar with over clocking. Tampering with it could do what? possibly kill my system?

    As well as is ther ea piece of software that i could use to check stability? Its currently running Os 9.2.2. And last week just for kicks i poped in a old 4gb drive and installed 10.2 on it. Surprisingly it was quite snappy. My plan is to up the CPU maybe the ram a bit and get it dual booting os 9 AND 10.2 or maybe 10.3 xpostfacto.
     
  5. desantii macrumors 6502

    desantii

    Joined:
    Sep 9, 2006
    Location:
    Aurora, IL
    #5
    As long as you play only with pins 1-4 (multipliers) you should be ok. Try 266 first before 300

    t
     
  6. catzilla macrumors 6502

    catzilla

    Joined:
    Dec 15, 2013
    Location:
    Rhode Island
    #6
    IIRC PCI bus is 33mhz and the memory is 66mhz. I still have a Molar running a G4 at 466mhz. I probably messed with the memory speed, but you would have problems if you are using PC66 ram. I wonder if the system profiler (or whatever the OS9 version is) will tell you the other speeds...
     
  7. comda thread starter macrumors 6502a

    comda

    Joined:
    Mar 15, 2011
    #7
    always wanted a Molar mac! I remember when i first saw it appear on an old TV show called "Double dare 2000" I thought it looked cool. Coolest beige computer design at least.

    Anyways i just want to get a little more out of this old beast. its a fast os 9 machine thats for sure. Currently i cant work on it as im back at my school dorm but during certain weekends i might.

    Do i actually have to buy jumpers though? like is it a jumper block or are there seperate jumpers? i havnt really looked.
     
  8. catzilla macrumors 6502

    catzilla

    Joined:
    Dec 15, 2013
    Location:
    Rhode Island
    #8
    At one point I had two Molars, one beat up one I got for cheap at a thrift store and one from ebay. I scavenged what I could and threw out the broken carcass.

    They come with a color coded jumper block for each processor. You may be able to carefully move the jumpers but it would be much easier to get new jumpers. Someone posted a link for a bag of 100 on ebay.
     
  9. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #9
    Buy the jumpers...I don't know of any source for the pre-made blocks, and I don't think that Apple made one that would do what you're trying to do.

    Having individual jumpers makes playing with this stuff VERY easy.

    The link I posted above was $8 including shipping for 100, or $.08 each. I don't think you'll do much better than that.
     
  10. comda thread starter macrumors 6502a

    comda

    Joined:
    Mar 15, 2011
    #10
    no no.. im not asking if there is a reconfigured one. im asking if the stock jumpers are seperate little jumpers or just one block. and i dont really need 100 hah
     
  11. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #11
    The stock jumpers are one block that is removed as a unit.

    When I was shopping it was about $5 for 20 jumpers or $8 for 100 at least when buying from US based sellers. 20 will be enough for one beige(I think it only has 9 jumper pairs), but I went with 100 since I'd planned to do both a beige and at least one if not a couple B&Ws(14 pairs).

    These jumpers are also the same as are used on many SCSI drives to set IDs and termination, as well as on laptop IDE drives to designate slave or cable select. If you play with old computers very much, you will probably find a use for more than 10(although admittedly 100 is a lot). Unless you plan for this to be your only project, I'd suggest getting extra.

    By the way, if you don't mind waiting on the slow boat from China, you can get the cost down to $3.28(including shipping) for 100.

    http://www.ebay.com/itm/100pcs-mini...546?pt=LH_DefaultDomain_0&hash=item35c334e9da

    (again, no connection from seller, and have not bought from them).

    Since I was anxious to get to work on my projects, I opted for a US based seller. The one I linked to above got them to me 3 or 4 days(I think) rather than the 3 weeks or so it would have taken to get them from China.
     

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