Apple/ Mac Memory

[yaronof]

I own a "late 2008" 13.3"" aluminum Macbook, 2.4G. 

A couple of weeks after installing the Crucial 4GB memeory upgrade (DDR3 PC3-8500) I started to experience very strange behavior.

I opened an email message and viewed a pdf attachment using "quick look".  Everything seemed normal.  Then I tried opening the pdf with "Preview" and the contents was garbled, i.e. the character set was completely giberish.  The strange thing was that when I opened the document again using "quick look", it was garbled there too now.  The next day, I opened the document using "quick look" and it was fine.  I closed and reopened, and it was garbled again!!  Although I can't swear to it, it seems to me that some of the characters were getting corrupted as I was scrolling through the document.

I copied the attachment to a folder on my hard drive.  Same results - garbled.

Interestingly, when I opened the same pdf from that same disk location in VM Fusion using the Windows XP I have on the same Macbook, the results are consistently as they should have been all along.

This leads me to the conclusion that something is going on with my hardware, because the file is not being changed and the software application that displays it isn't changing.  The only thing that changes here is the memory, through which I see it on my display.

That by itself would not have alarmed me as much, if it hadn't been for 2 more wierd things that happened yesterday.

One, for a short time (about an hour or two) whenever I tried to invoke the "Address book" application using Quicksilver, the icon that showed up for "Addressbook" was wrong.  That never happened before.  Very, very strange.  Later in the day, the correct icon showed up again.   All along, the icon on the application ruler was fine.

Two, in NeoOffice, an embedded jpg disappeared from two documents.  In one document, it returned on its own later on.  In the other document, it's still missing, giving a "Read error".  I verified that the jpg is embedded, not linked.

I would appreciate any thoughts on this.  Prior to purchasing the RAM upgrade, I had heard that there were compatibility problems with  non-Apple memory for these machines.  Please help me with some answers here.

Thank you,

Yaron.

[lordgllynn]

Have you tried Memtest yet? Since the possibilities and causes for software corruption are infintessimal, it's best if we eliminated hardware possibilities first. Test your memory with MemTest86+. It runs outside of Mac software, so it is much more reliable. Test using one stick at a time and try all of the slots as well. Let us know if you find anything.

[yaronof]

Update:

I spoke to Eric at Crucial Tech Support.  He recommended a couple of things to start with, and there are good results already.

First, he told me to do a pram, i.e. restart holding the control-option-P-R keys.

Once I did that, one of the problems simply went away.  The problem described above with a garbled character set displayed by "quick look" and "preview" of the pdf file, has simple gone away.  I keep going back and looking at the file again, but it really and truly seems to have been completely fixed simply by performing this pram action.

Eric also recommended that I download and run "rember", which I did, and the test results are good.  The only problem is that the log shows that it only ran the test on some 2600MB because that was all that was free, even though I specified "all" for testing. I wonder how it could ever possibly test everything, because there would always be some memory that wouldn't be free.

As for the other two problems I reported, I'll be on the lookout to see if they recurr. I will update this post if they do.  For now, I'm a happy camper.

Please pass my sincere thanks to Eric, who was very patient and attentive, and very helpful (with good results, as it turns out.)

Yaron