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so i brought 1GB yesterday for my brand new 24" iMac and it doesn't fit? how chould this be? its PC2-5300 which looks like the right code but the dimensions of the chip are slightly bigger than the one already in the machine..

anyone have an idea on what the problem is? thanks

Not sure what could have caused it, but the best solution I can think of is to take both pieces of RAM back to MM and make sure they replace it with one that matches the original.

We buy all our RAM through MM (last lot was 60 x 1GB modules for 20" iMacs) and they've always been good at replacing any faulty modules.

Are the dimensions actually bigger?

Sometimes when placed into the slot you might be out a fraction and while it looks bigger it's more a matter of not having it correctly aligned. I've made that mistake myself.

Remember RAM can only go in one way so there's also the possibility that you have the DIMM around the wrong way.

Also check to see how many grooves there are in the DIMM. There should only be one but there may be two which will be the wrong DIMMS supplied.

yeah, i took out the existing chip to compare them. on first glance they appear the same, but on closer inspection they are the same length, but the new one is about 2-3mm deeper. it also has some extra componentry.


there is only one Groove towards the lefthand side.


oh well, back to Magnum as they're not open tomorry

PC2-5300 & PC-5300

thats the only discrepancy i can find online. some apple sites list one, and some sites the other. not sure which one im meant to have. the one i brought is PC2-5300 and thats what the apple store lists for my iMac too

I've never heard of "PC-5300" as a RAM type, except in error.

Dual data rate SDRAM goes up to PC-3200. After that they introduced DDR2, which started at PC2-3200 and seems to go up to PC2-8500, if Wikipedia is right.

Your RAM may in fact be perfectly OK. It is normal for memory modules of the same type from different suppliers to have a different chip layout, a different number of chips, and possibly be taller or shorter.

It should work in an iMac as long as it the correct basic type (200 pin PC2-5300 SODIMM) provided it is known to be Mac-compatible (which it must be if MagnumMac sold it to you).

The extra height does not matter as long as it is no taller than the limit specified by Apple for that Mac model. According to Apple's developer note for the August 2007 iMac:

"The iMac provides two RAM slots that accommodate 200-pin DDR2 SDRAM SO-DIMMs up to 1.25” in height. The SO-DIMMs must be DDR2 PC2-5300-compliant and must be unbuffered, unregistered, 8-byte, nonparity, and non-ECC. Both 20” iMac and the 24” iMac ship with one 1 GB DDR2 SDRAM SO-DIMM. Maximum memory capacity is 4 GB."

Note the maximum height is 1.25 inches (31.75 mm).

The very latest iMac (released last Tuesday) has the same physical specifications but it requires PC2-6400 memory (and is the first Mac to do so).