MacBook fussy memory situation- maybe 4 GBs is too much

My story about how the new aluminum MacBooks are pretty darn fussy about third party memory upgrades has touched the nerve of quite a few folks.  To recap, my attempt to replace the 2 GB (2 x 1 GB sticks) of memory that Apple shipped in my MacBook with 4 GB (2 x 2 GB sticks) of Crucial memory didn’t go well.  The MacBook immediately began freezing up, sometimes with a garbled display, requiring a hard reboot.  My research online pointed to quite a few folks who have discovered the same thing and while some third party RAM works in the new MacBooks some doesn’t.  There’s no rhyme nor reason as some are having good luck with some brands and others are faced with system hangs using those same brands.  The only constant in this memory upgrade problem is that memory sold by Apple, either Samsung or Hynix, always seems to work fine.

3_gb_mbThis weekend I did some testing because I wanted to get a feel for what is causing these memory upgrade problems.  The 4 GB of RAM I bought from Crucial causes the MacBook to have the freeze-up problem consistently.  I put the 2- 2 GB sticks of Crucial memory and within an hour the MacBook started locking up.  I can put the two Samsung sticks back in and the problem goes away every time.  Logic would dictate that there is likely something wrong with one of the Crucial memory sticks since failure happens every time both are put in the computer.

I tested this conclusion by putting one Crucial stick in along withone of the Samsung sticks that Apple provided with the MacBook.  Thisgave me 3 GB of total RAM in the MacBook and I expected it to startfailing.  It didn’t, instead it ran for a day with no problems.  OK, Ifigured that the other Crucial stick must be the bad one so I swappedit with the Crucial stick that is working fine.  This 3 GB of memoryhas been in the MacBook for over a day and it’s working fine too.

This is a bit confusing because in my experience RAM sticks areeither bad or good, no in-between.  Yet either of the Crucial stickswill work fine alongside either of the Samsung sticks.  Put both of theCrucial sticks in at once and the system fails predictably. This is not logical to me but then I’m not a computer memory expert.

It leads me to wonder, do the new MacBooks have trouble with over 3GB of memory installed?  My system is not picky what combination of the4 RAM sticks I use it always runs fine with 3 GB of RAM but it alwaysfails with the 4 GB of Crucial memory.  Remember that Crucial memoryruns fine singly, it just won’t run with both in together.  The onlyconclusion I can reach is that the MacBook doesn’t like 4 GB of RAMwith the Crucial sticks.  This is very strange to me.  There isactually another conclusion that I can reach, the system always failswith no "official" Apple memory installed. 

I made an observation during this process that I find interestingeven though it may have nothing to do with this memory strangeness.The MacBook and OS X reads the RAM sticks and reports the vendor andserial number of the stick.  The Samsung memory that is used by Appleduly reports those ID numbers as you would expect but the Crucial RAMsticks do not have valid numbers reported by OS X.  So the Mac knowsthese aren’t "official" memory sticks.  Hmmm…

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UPDATE: owners of new MacBook Pros are reporting this same memory madness and even with Apple installed memory.  This is quoted from a commenter on the Apple support forum:

News from Apple re the Freezes!

Following my conversation with Mary at customer services (who called mein reply to my email to Steve Jobs – I kid you not, that’s what shesaid) I was called yesterday by an Apple engineer.

He told me the following:

Apple are very aware of this problem.

It is ocurring to people who have max amounts of RAM in their machinesand apparently it makes little difference if it is Apple RAM or 3rdparty – it is the quantity that matters.

They are about to release a software update to address it. He said thatofficially it might take up to a week or two for this to come out butunofficially we could expect it within a matter of days.

In the meantime he said that a solution could be found by removing oneof the 2GB sticks and replacing it with the original 1GB – I asked ifit was a problem running unequal banks and he said no, only on theMacBooks as they share the RAM with the GPU which these MacBook Pros donot.

We may therefore get deliverance soon, everyone! Hurrah.

BTW what happenend to 10.5.6 which apparently was almost ready forrelease about a week ago and suddenly nothing – do you think that theRAM fix may be being bundled into it?

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