Mac Pro runninng Lion. AHT and memtest disagree on memory

Question

Mac Pro runninng Lion. AHT and memtest disagree on memory

The essential is in the title. Some months ago, I gave Apple Hardware Test a run from my Intallation disk . My Mac Pro is an early 2008, with 24 GB memory, an eSata II PCI card and an USB3 PCI card. I diconnected all peripherals, as requested, but didn't plug out the PCI cards. The A H T gave a general satisfecit , except for an obscure Memory error.

I must confess that the memory is a mix of Apple and 2 other providers (one being Crucial) . Obviously another test , specific to memory, had to be done.

I used the latest version of memtest in Single User Mode. Memtest correctly locked the memory and checked the maximum allowable ( about 22,5 GB)with three passes. Everything was three times found OK.

Which test is right ? IMHO Apple Test Is the culprit , at least as far RAM is concerned.

Moreover it is of little value as it does'nt explain what exactly it finds wrong with the memory

Francois Joly

Mac Pro, Mac OS X (10.7.4)

Posted on Jul 16, 2012 2:53 AM

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Answer 1

mende1

Level 10

93,538 points

Jul 16, 2012 2:56 AM in response to Francois JOLY

I think the memory is correct, because Apple Hardware Test is for Apple hardware

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Answer 2

The hatter

Level 9

60,990 points

Jul 16, 2012 3:44 AM in response to mende1

RAM is not "Apple" and whatever you have, but without posting what AHT error was.

Most common is to see FBDIMMs fail and show the wrong size or amount in which case it is just plain defective and needs to be replaced thru RMA or on your own.

And it helps maintain RAM to insure it never goes above 70*C.

memtest from terminal is nice as you can run dozens of concurrent tests - say 48 with each testing 512MB (approx.) for 4-5 loops. And some use Rember - same memtest just with GUI and that seems to do an excellent job but takes longer.

Apple is the only one that knows AHT errors. Sometimes you can Google and find others with same error code.

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