11-22-2008, 09:26 PM

Hi Guys,

I'm awaiting the arrival of an iMac G4 I bought off eBay for friend of mine. It only has 256MB of RAM so I'm looking to get it up to 1G through using two sticks of 512. Being in Australia I'm on the national eBay site and found this:

512 Mb RAM memory for iMac, eMac, or G4 tower - eBay Memory, RAM, Accessories, Parts, Apple, Computers. (end time 26-Nov-08 18:54:03 AEDST)

If someone could tell me if that RAM is compatible with a 800GHz machine that'd be great (PowerPC of course), as I'm not sure about the RAM requirements in the G4's. Thanks in advance =)

11-23-2008, 05:06 AM

Whoah, an 800 Ghz iMac? That has to be the fastest computer ever built!

Anyway..

The iMac G4 uses two different types of RAM, a full sized DIMM and a laptop size SO-DIMM. The only officially upgradable one is the SO-DIMM which is user accessible on the bottom of the iMac. In order to replace the factory installed RAM it is necessary to take apart the base of the computer, which is considered by some to be difficult. Personally, I don't think it is that hard to do at all, but there is a very important step which must be taken when taking apart a G4 iMac. If the bottom of the computer is removed, it is necessary to apply new thermal paste to the heatsink which routes heat from the processor up into the top of the case near the fan. If you don't do this you could overheat and permanently damage the system.

The RAM you posted will work to replace the factory installed DIMM. For the other one you will need a PC-133 SO DIMM. The max it will take is 1 Gb.

Here is a decent guide which will walk you through the process of taking apart the computer.

Good luck!

11-23-2008, 05:22 AM

Hahaha whoops, I don't know where that 'Ghz' came from lol my bad...

Okay sounds good. I'll have a look around and see if I can get my hands on some of that SO DIMM RAM =)

The guide looks pretty simple to follow so I'll see how I go. Thanks or your help!

03-07-2009, 09:44 AM

Hey there,

I just purchased a secondhand imac G4 1.25Ghz. The unit has about 1GB of ram. I was looking to upgrade them to about 2GB.

Is it possible to take it more?? I thought that if I purchased a 2GB PC2700 SoDimm and a normal Dimm 2GB PC2700, I could probably take it upto 4GB of ram. And on a machine like the imac G4, that would be amazing.

Is it a good idea???

03-07-2009, 10:10 AM

No, it won't take 4 GB no matter what you do. This is a limitation of the hardware. The 1.25 GHz model will take 2 GB, with a 1 GB PC-2700 SO-DIMM and one stick of 1 GB PC-2700 SDRAM.

03-07-2009, 10:15 AM

Originally Posted by knightjp

Hey there,

I just purchased a secondhand imac G4 1.25Ghz. The unit has about 1GB of ram. I was looking to upgrade them to about 2GB.

Is it possible to take it more?? I thought that if I purchased a 2GB PC2700 SoDimm and a normal Dimm 2GB PC2700, I could probably take it upto 4GB of ram. And on a machine like the imac G4, that would be amazing.

Is it a good idea???

you will have to worry about the memory controller on the g4 imac. i read on a page it can officially support 1gb and unofficially support 2gb. if you go with the 2g you may see lower performance than the 1gb.
again here is the link Apple iMac G4/1.25 17-Inch "FP" (USB 2.0) Specs (iMac USB 2.0 - M9168LL/A) @ EveryMac.com

03-08-2009, 03:15 AM

Originally Posted by R0GV3

you will have to worry about the memory controller on the g4 imac. i read on a page it can officially support 1gb and unofficially support 2gb. if you go with the 2g you may see lower performance than the 1gb.
again here is the link Apple iMac G4/1.25 17-Inch "FP" (USB 2.0) Specs (iMac USB 2.0 - M9168LL/A) @ EveryMac.com

The link you gave didn't mention anything about the memory controller.
Any other links available?

Has anyone here upgraded the ram to 2GB?

03-08-2009, 12:59 PM

You won't see a performance decrease. I have a 1 GHz iMac G4 which used to be my main computer, but is now more of an art piece. I upgraded from 1 to 2 GB of RAM a few years ago and the performance increased dramatically. The only reason it is listed as being officially upgradable to only 1 GB is because Apple does not consider the RAM slot inside the case to be user serviceable, since it requires a fair bit of disassembly and would void the warranty, which is now long expired anyway.

03-08-2009, 09:44 PM

so are all of the G4 imacs unofficially upgradeable to 2gb of RAM?

03-08-2009, 10:40 PM

When you consider replacing the internal RAM, instead of putting a 1GB on it, why can't we put in a 2GB?
Is there something somewhere that suggests that we cannot put in a higher capacity RAM?

I know that with normal IBM compatibles, the RAM capacities could be changed to higher ones provided that the RAM ran at the right clock speed.

03-08-2009, 11:14 PM

The logic board in the G4 is limited to seeing only 2 GB of RAM. You can install more, provided it is the proper speed, but it will only see 2 GB. Actually, the iMac may not even start up with more than 2 GB installed. There is no way to get around this limitation. This system is not like a normal tower PC. It is a completely custom design which is not versatile at all when it comes to upgrades, and therefore the capability of seeing larger amounts of RAM were not built into it.

03-09-2009, 12:12 AM

Well then I guess that 2GB would have to do.

I would like to know if anyone has ever tried to put in more ram though. It would be awesome to have it upto 4GB.

03-09-2009, 02:37 AM

Go ahead and try, if you don't mind spending the money on old DDR RAM which is actually more expensive then newer DDR2. If it works then definitely let me know; I love when I am proven wrong. I haven't tried it myself since I don't have a memory module larger then 1 GB of DDR laying around.

03-09-2009, 10:37 PM

Originally Posted by ADKhikerVW

Go ahead and try, if you don't mind spending the money on old DDR RAM which is actually more expensive then newer DDR2. If it works then definitely let me know; I love when I am proven wrong. I haven't tried it myself since I don't have a memory module larger then 1 GB of DDR laying around.

Will do....

Now all I have to do is source out 2GB DDR PC2700 ram

03-10-2009, 03:18 AM

i am a pc user ... yah yah i know... but im getting closer to the dark side ... anyways .. my aunt asked me to help her upgrade her mac's ram and i dont really have a clue concerning macs. i've gathered this info from the system and i realize that its a old comp but is there anything we can do to breath some more life into it? all it is used for is to surf the net and nothing else. I dont even think there is anything installed on it other that whatever comes with that operating system. the computer was given to them by a friend so she could use her email program and firefox to keep in touch with family. so theres not much else it does other than surfing and emailing i believe.

running mac os x version 10.3.9

Power PC G3
128 mb SDRAM
400 mhz

cpu type: PowerPC 750(83.0)

any info would be greatly appreciated. let me know if any other info is needed

i kinda thought if i could put the max amount of ram i could into it it might help somewhat. anyone know how much i could put into it? and what types i can use? looks like its pc100 in it now ... will it take pc133? pc133 seems to be more easily findable

thanks
Adam

*found some more info that im 100% sure on but pretty certain its right.

looks like its an iMac G3/400 DV SE (Slot Loading) 400 MHz PowerPC 750 (G3) at least thats what im going with based on appearance and color of the unit and specs ive found online.