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iMac G3 upgrades

Discussion in 'PowerPC Macs' started by zackkmac, Apr 28, 2013.

  1. macrumors 6502a

    Hi all. I have a slot-loading iMac G3 that has been sitting unused for a while and I'd like to do what I can to make it run its best. It is a 400MHz graphite model with 1GB RAM, AirPort, and a 160GB HD (seen as 128GB).

    I know I have the RAM maxed out, and I plan on purchasing a CF card + adapter setup to replace the HD, so that leaves me with the processor.

    I have found a 700MHz logic board, and it's the same shape as my current one, so it seems like it would fit fine but does anyone know for sure?

    Also, I found a guide over overclocking these iMacs by changing the resistors on the logic board. They list speeds of up to 1GHz. Would that be safe for the iMac or would it not run at 1GHz? There are a lot of speed bumps on the list that would be an improvement over the 400MHz without having to buy a new board - any comments/suggestions?


    Thanks in advance!
  2. macrumors P6


    400Mhz+ G3 iMac logicboards are all swappable without any need for a change. You really can't overclock the 700Mhz beyond 700Mhz because that's the limit of the G3 chip used in it. They won't run past it. The 400Mhz logicboard can be taken up to 450Mhz or 500Mhz before they start to become unstable.
  3. macrumors 6502a

    I see. So I think I may stick with purchasing a 700MHz board and a CF card. To me that is much easier than soldering those resistors over and over and potentially ruining the logic board. Thank you!

    Only thing, so far the only 700MHz board I can find is $100 which is a lot to drop on the old G3. For that price you'd think it would just be better to buy a 700MHz iMac complete but I can't find any. And a lot of the G3's on eBay are slower than 600MHz and over $100.

    Also, would it be easy and inexpensive to swap the sleep indicator out for one that glows white? I love the white sleep LEDs on most Macs and these are orange/green. Obviously not a huge concern, but if I can find the part cheap it would be a fun little mod. :)
  4. macrumors 65816

    Lil Chillbil

    not that much upgrades you can really do to these imacs, much like current imacs its mainly hdd and ram
  5. macrumors P6


    700Mhz G3 iMacs go for quite a bit because they're 700Mhz and weren't sold for very long. I think the G3 iMacs sold after 2001/2002 have white sleep leds.

    You can also upgrade the CPU in current iMacs.
  6. macrumors 68040


    Yep. My Snow has white one.

    OP: your best bet would be to get 600 MHz one (or only logic board) and OC it to 700. 600 MHz ones have exactly the same specs as 700 MHz model except CPU freq.
  7. macrumors 6502a

    Interesting info. If the 700MHz iMacs do have a better value, then maybe $100 for the 700MHz logic board isn't terrible. What do you guys think?

    666sheep, that is another idea I'm considering, but I've also never had any experience doing something like that. So I'm a bit afraid I'd mess something up. Plus, I have no tools to do so, so the 600MHz iMac (or board only) + soldering tools would end up being more costly than just dropping in a 700MHz board. I was really only wanting to overclock if I could bring my current 400MHz board to at least 700MHz but that doesn't sound doable.

    Now I wonder about the sleep light. Is the LED on the logic board, or a different assembly I'd have to purchase? If it's on the logic board then I assume the new 700MHz board will change the sleep light to white.
  8. macrumors 68040


  9. macrumors 6502


    The charm of owning a G3 iMac has faded for me, though I did spend a bit of time looking for one in January and March.

    I'd go for a 600MHz model as well. These are frequently offered on New York's Craig's List for less than $100. Most are in good condition, and some have been upgraded in other ways than the LB. I wouldn't pay anywhere near $100 for a 700MHz logic board.
  10. macrumors 6502a

    Thank you for that!! And yeah, usedmac.com is the one that turns out to be around $100 after shipping and tax. It's just hard to pull the trigger on that for a 13 year old desktop. But UsedMac has had these in stock for so long, I wonder if they would let me make an offer of like $50 or something just to get it off their hands.

    I like that snow iMac but it's not in my area. :( I'd probably have to get one off eBay and have it shipped.
  11. macrumors 6502


    I haven't checked today, but there was recently a G3 iMac on New York's Craig List advertised as "SEALED" for a hundred bucks. Think it was either 400/600MHz.
  12. macrumors 6502a

    Interesting...I wonder if someone already bought it. I found it and e-mailed the seller. Not in my area but if the seller is willing to ship I'd gladly pay that and postage. :D

    Another reason why I am upgrading this iMac is I have some leftover credit on my credit card bill and really would enjoy maxing out my G3 with that money. We want to use it as a kitchen computer for recipe lookup, storage, and music playback. I think a 700MHz 1GB with flash memory running 10.4 would do well as a light task machine. :)
  13. macrumors 6502


    Well, yeah, it'll easily handle those tasks. Also decorates well.

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