How much memory can I put in a G4 iMac?

I just bought a second-hand G4 iMac 1.25MHz, 20". It has 768Mb installed on it (I don't know the configuration, I am still awaiting delivery). According to some the max memory is 1Gb (supported by apple!), but elsewhere suggests 2Gb is maximum memory achievable.
I had the very first iMac and am glad to be back in the fold after a decade in windows wilderness.

2GB and here are the specs of the 1.25GHz I take it:-

http://www.everymac.com/systems/apple/imac/stats/imac_1.25_20_fp.html

Thank you. That is GOOD news

divergordon said:

Thank you. That is GOOD news

Click to expand...

Also realize that you need two different sized "sticks" of ram to max out the memory to 2 gig.

- Nick

Thank you. Can anyone advise on where I should shop (UK).

2 IGB sticks of PC2700 (333 MHz) DDR SDRAM

20" iMac G4/1.25 GHz

Since i am in the USA I will let someone in the UK answer the best place to purchase. I would say OWC but not sure on UK delivery.

EDIT: OWC does do worldwide shipping so it might work for you. If you go with then everything is guaranteed to work on your Mac. If not they will make it right.

G4 iMac 1.25ghz...PC2700 (333 MHz) DDR SDRAM:

†† These models have one factory installed memory module in a 184-pin DIMM slot (the difficult to access top slot), and one 200-pin user-accessible SO-DIMM slot (the easy to access bottom slot).

How do you upgrade the RAM in the iMac G4 models?

If you're in the UK...no problems ordering from OWC:

Memory, more at OWC

Folks from the UK & Australia have reported great service & delivery times.

- Nick

I advise the OP to use GREAT caution when upgrading the "inner" memory module: it's not just a different size, you have to take the machine apart to get at it AND you have to replace the thermal paste (not too little, not too much!) when doing so.

We saw a LOT of destroyed G4 iMacs that came from people upgrading the RAM without realising the thing about the thermal paste, and a few from people who just slathered the paste on like it was spaghetti sauce. Both caused a lot of damage.

chas_m said:

I advise the OP to use GREAT caution when upgrading the "inner" memory module: it's not just a different size, you have to take the machine apart to get at it AND you have to replace the thermal paste (not too little, not too much!) when doing so.

We saw a LOT of destroyed G4 iMacs that came from people upgrading the RAM without realising the thing about the thermal paste, and a few from people who just slathered the paste on like it was spaghetti sauce. Both caused a lot of damage.

Click to expand...

Yeah I've done it. Replacing that "inner" ram module is certainly harder than your "normal" ram upgrade.

Like you said:

- a good bit of disassembly
- wires & components dangling everywhere (easy to damage some of the "finer" gauge wires)
- when laying the computer on it's side, got to be careful to protect the display
- and of course cleaning up & replacing the thermal paste.

Good learning experience though for the "Do-It-Yourself" inclined owner!

- Nick

thanks guys. A bit of good news/bad news there. Hmmmm, maybe I can survive with 1Gb memory...........

divergordon said:

thanks guys. A bit of good news/bad news there. Hmmmm, maybe I can survive with 1Gb memory...........

Click to expand...

Hey don't give up on your project if you want to upgrade this iMac G4 to 2 gig. We are just letting you know what's involved...so you have a better idea what to expect.

In any case...I think that if you purchase a 1 gig ram module for the "user accessible" ram slot...you will still have 1.25 gig of ram (1 gig + a 256meg ram module in the harder to access ram slot).

!.25 gig will certainly be better than 768meg. But go for the 2 gig if you feel you have a "handle" on what's required.

Good luck,

- Nick

Thank you very much Nick. You have been very helpful. The machine is due to arrive soon. I will have a look and the decide. I also have to install an airport card.

Gordon