Overclocking G3 Powermac

Discussion in 'PowerPC Macs' started by supermario19, Mar 8, 2007.

  1. supermario19 macrumors member

    Aug 17, 2006
    Ok so I bought an old beige desktop g3 powermac. I'm loading it up with ram, and I would like to overclock it as well. It is a 266, and according to resources I found, I can get it up to about 500 or 600, 666mhz i think. some using the jumpers on the motherboard, but the only success stories I've heard are people that only up it to about 300. So does anyone know if it would be somewhat safe to try it at the max, maybe with a fan or two? Or should I just stick to a lower, less fun, speed?
  2. yellow Moderator emeritus


    Oct 21, 2003
    Portland, OR
    I'm surprised that it could get any further than 300MHz.
  3. supermario19 thread starter macrumors member

    Aug 17, 2006
    Ya I'll be surprised if it goes over 300 too, but I was hoping someone would know for sure before I go and fry a perfectyly good mac.
  4. livingfortoday macrumors 68030

    Nov 17, 2004
    The Msp
    I've only gotten my 266 a little over 300 and kept it stable. I seriously doubt you'll get much higher, since a lot of other factors like the PCI speed and the RAM come in to play.
  5. AdamR01 macrumors 6502

    Feb 2, 2003
    I only got my 266MHz PowerMac up to 300MHz when I had it. What I noticed though, was that it ran faster at 292MHz. This is because at 292MHz, the multiplier is only 3.5, but the Front Side Bus Speed is 83MHz instead of 66MHz. This seemed to make a whole lot more of a difference than a 33MHz increase in clockspeed. I would only recommend this if you have PC100 memory in your PowerMac though, as PC66 tends to not like running overclocked. An 83MHz FSB still runs the PCI bus at 33MHz so you do not have to worry about funky stuff happening. This was with no additional cooling as well.
  6. Niftium macrumors newbie

    Oct 20, 2006
    I think the rule of thumb on overclocking is +15%. (Anyone who knows otherwise, feel free to correct me.) So I wouldn't expect a whole lot of functionality out of a 266 OC'd beyond 300.
  7. supermario19 thread starter macrumors member

    Aug 17, 2006
    Thanks for the tip adam. Thats a good idea having the bus higher. and I'm pretty sure all I've got in there is at least pc100, maybe even pc133 ram, so I should be in the clear.
    I do have a fan off of a pc heatsink, and a connector to get power off of the hard drive power cable, only problem is, with the flip design theres no room for it. I might cut a square into the metal casing above it, since its empty space anyways, but I'll see how this goes.

Share This Page