Rev A iMac Mem?

ezra

Super Organism
My sister has a Rev A iMac she wants to upgrade to OsX, so I said I would help her. I ran into a problem when I went to install the memory. The Upper slot was no problem, but the lower slot was to small for the other 256 module I purchased. I was assured that the machine could hold 512MB. Was I lied to, or is there a special module for the lower slot?
 

Klink

Member
There certainly is a size difference between the upper and lower slots. Unless you specifically ask for the module for the lower slot, most retailers will sell you the top slot modules thinking most people won't pull apart the CPU daughter card.

If your retailer is any good, he/she should exchange it with the proper size module.
 

ezra

Super Organism
Originally posted by Klink
There certainly is a size difference between the upper and lower slots. Unless you specifically ask for the module for the lower slot, most retailers will sell you the top slot modules thinking most people won't pull apart the CPU daughter card.

If your retailer is any good, he/she should exchange it with the proper size module.
Thanks fo the info, I return the module, and hopfully get the correct size this time.
 

anerki

Registered
Hyo

I didn't know a revision A could hold that much RAM??? I was always told that 256Mb was the max for those "older" machines. Mine only holds 256Mb ...
The size of those two slots should be the same (both SODIMM) but I fear the maximum thickness of the lower slot is less. Does the 256Mb RAM in the upper slot work???
To get access to the lower slot, remove the metal holder for the cooler plate. Just push the looser end down or pull it up, anyway, un-click it, and then remove it. Now remove the cooler. You should see the lovely little brain of your iMac now.
Now, you have two options, the way I first did it, and the way I did after the first time.
1) Just force the metal fence from around the daugther card and you will be able to pull it out and put in the RAM.
2) The way you should do it is just grab the daughter board where you can reach it, and pull it up. You'll be able to slide it out, don't worry to put a little muscle in it, just don't break it :D
Now do the exact same but in the other direction to close the board again, hope this helps ;)

Ciao
.anerki
 

ezra

Super Organism
Originally posted by anerki
Hyo

I didn't know a revision A could hold that much RAM??? I was always told that 256Mb was the max for those "older" machines. Mine only holds 256Mb ...
The size of those two slots should be the same (both SODIMM) but I fear the maximum thickness of the lower slot is less. Does the 256Mb RAM in the upper slot work???
Yes, the chip works fine, and the lower slot IS shorted than the upper slot, not thinner that I can tell. It's shorter because the CPU is in the way.


To get access to the lower slot, remove the metal holder for the cooler plate. Just push the looser end down or pull it up, anyway, un-click it, and then remove it. Now remove the cooler. You should see the lovely little brain of your iMac now.


Taking the iMac apart is no problem. I build computers all the time. THe macine holds 384MB according to specs, but some say there is a 256MB that exists somewhere that will fit. I havn't found it. I sent my chip back in exchange for a 128MB.
 

RacerX

Old Rhapsody User
I've been upgrading quite a few iMac lately (mostly people with 32MB wondering why their system is so slow, they are usually amazed after the upgrade), you can get the upper DIMM in 256MB for about $40 and the lower (usual referred to as low profile) for about $90. I've been working with Mac Solutions (see: http://www.macsolutions.com/ ) and they have both type in stock.:D
 

benpoole

Registered
I have a rev B iMac and just recently updated its memory from 32MB to 256MB -- the "underside" RAM upgrade is a little tricker than the top slot one, but not too bad.

I'd recommend this site for piccies of how to get to the slot:

http://www.theimac.com/ram_under.shtml

You need "Low profile" chips for the bottom slot, whereas either profile works in the top. Most places sell 32MB - 256MB chips as low profile nowadays (as a rule of thumb, they're about and inch deep and three inches long?)

As for the memory limits quoted on apple.com, these are old, based upon the chips that were available and the testing done when the various iMac models were released. So don't necessarily be shocked if someone says they have a 1 gig iMac rev A... It can be done!
 

ezra

Super Organism
Originally posted by Doraemon
Actually, a iMac Rev A / B can only hold a max. of 128MB RAM. At least, that's what Apple supports.


http://www.theapplemuseum.com/products/personal/imac/bondi.html
Don't believe everything you read, I initially started this thread asking how much was possible. I put a 256MB chip in the upper slot, and a 128 MB in the lower slot. It dosn't give me the full 384MB, but it does give me 340MB, which is plenty for this machine. It only cost me $45.00 as well!
 

RacerX

Old Rhapsody User
Originally posted by Doraemon
Actually, a iMac Rev A / B can only hold a max. of 128MB RAM. At least, that's what Apple supports.[/url]
Apple does not upgrade their specification from the time of release of a given product. At the release of the iMac, the largest DIMM you could get was 64MB (two of which gives you the original max of 128MB). As has been seen here, you can get large DIMMs for the iMac today. The slot-loading iMacs were thought to have an upper limit of 512MB, but with DIMMs as large as 512MB that are currently on the market, 1GB is now the upper limit (just don't expect to see Apple rewrite any of their support manuals to reflect this).:D
 

ezra

Super Organism
Originally posted by MacCheetah3
Hi
Those are the original release specs. The top is 2" and the lower is 1.5" i believe or maybe even 1". The iMacs are a 4@$@% to take apart and put back together. Go here for the upper http://www.macsales.com and here for the lower http://www.transintl.com. Oh and the original hard drives are small and slooooowwwww. Good Luck!
It really depends how familiar you are with them I guess, I find it pretty easy to get to most of the hardware. It really only took about five minutes to get in-out and boot ,but were working on machines all the time. The lower chip they shipped me was a 1" btw.
 
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