View Full Version : Overclocking a G3...

Aug 17, 2008, 06:47 PM
I tried a google for this and I either got results for the tray-loading iMacs or forums where people who asked don't get replies. I hope we change that lol. And I did see the other thread here that relates to this, I thought this could be a new topic since it's not overclocking software I'm looking for. Unless there is some for the iMac G3...

My mom gave me this 400MHz G3 from her old office [who knew? she said she doesn't prefer Macs] and I read online how to upgrade the HD, so I put a 40GB one we had in it, and 512MB ram. Now I want to try upgrading the processor, which is probably soldered on. So is there a way to overclock it? Any speed bump would be fine :)


Aug 17, 2008, 06:53 PM
They make proc upgrades for it, you can put a G4 in it.

I am assuming you ar on a B&W G3...

There is a small strip made of plastic, pretty close to the processor. There might be a sticker thing over it that says, "warranty void if removed" pop that off. You can reuse the jumpers on there (or just use HDD jumpers) you can set the clock speed, and the bus speed. I brought my 350MHz G3 up to 400 however it isnt anywhere near as stable as it used to be. I was never able to get it to boot up if I tried to go any faster than 400...

There are diagrams and stuff out there that shows you how to position the jumpers for the respective speeds...

Aug 17, 2008, 06:58 PM
I don't believe its possible to overclock a G3 iMac.

Aug 17, 2008, 07:00 PM
Thanks for the replies but I'm talking about an iMac G3, the egg-looking one :p

Aug 17, 2008, 07:03 PM
I don't believe its possible to overclock a G3 iMac.

Really? Unless others say otherwise that's a bummer. :(

Aug 17, 2008, 07:09 PM
There is a way, pick up the G3 & replace it with a newer one (hope your not price sensitive)

Sun Baked
Aug 17, 2008, 07:11 PM
All depends on which CPU that specific G3 or G4 is.

Some were capable of overclocks. And other Apple got running at the maximum capable speed.

All depends on the process and whether IBM/Motorola were at a brick wall with that version of the GPU -- note the brick walls tended to happen quite a bit with PPCs.

Note: G3 and G4 were blanket names for a bunch of CPUs that went through drastic changes and versions, the first ones were generations apart from the last machines Apple sold.

Aug 17, 2008, 07:39 PM
Yeah, I'll probably just eBay a new board, I couldn't find a 600MHz one. I heard there were even 700MHz iMac's then, but I have never seen a logic board on eBay for one [I've looked a lot before].

Aug 17, 2008, 07:49 PM
700 MHZ G3 iMacs were extremely rare because they were overpriced for what you got and they weren't out for very long.

In this day and world upgrading a g3 processor at 400 mhz to a new one at 600 mhz isn't going to make much of a difference with internet since flash and everything else slows down old computers, but it should make a notable difference with old games, etc.

Aug 17, 2008, 07:50 PM
Check out the Overclocking section at Toms hardware

Sep 15, 2008, 10:00 PM
The slot-loading iMacs were harder to upgrade the CPU, however the Tray-loading iMacs had their CPU on a daughter-card, making it easy to swap it out for a faster processor.

I replaced the 233MHz CPU on a REV-B Bondi Blue iMac with a 333MHz card from a REV-D iMac. You can also purchase third party cards for these, however most of them are out of business now. I did see a 466MHz G4 (yes, a G4) upgrade go on ebay for $45 a few weeks ago, and i wanted it soo bad, but i was working when the auction ended.

I believe Daystar still sells a CPU upgrade for them. It's a 400MHz G4 that is just a plug-n-play upgrade for $99.