02-29-2012, 03:17 PM

Hi All,


Have posted the same topic elsewhere but I haven't really had the answers I had been looking for, so I am hoping here can shed some light on it.


Recently purchased new RAM for Macbook Pro Late 2010 Model (Still running Snow Leopard) , and now has 8GB on two 4GB Slots.


I was prompted to do a memory test to ensure they worked correctly, and the results are below. Test was not carried out in Single User mode and was done with no other apps running in terminal.

It has been mentioned doing the test in single user mode.

This is where the limit of my computer knowledge ends, so whilst I can see in black and white its stating there is a failure - should I be looking for a refund?



Anyone who is able to explain my failure would be great, as I am always looking to further expand my knowledge.


Thanks





Memtest version 4.22 (64-bit)
Copyright (C) 2004 Charles Cazabon
Copyright (C) 2004-2008 Tony Scaminaci (Macintosh port)
Licensed under the GNU General Public License version 2 only

Mac OS X 10.6.8 (10K549) running in multiuser mode
Memory Page Size: 4096
System has 2 Intel core(s) with SSE
Requested memory: 5442MB (5706547200 bytes)
Available memory: 5442MB (5706547200 bytes)
Allocated memory: 5442MB (5706547200 bytes) at local address 0x0000000101000000
Attempting memory lock... ERROR: Memory lock failed - reason unknown.

WARNING: Testing with unlocked memory may be slower and less reliable

Partitioning memory into 2 comparison buffers...
Buffer A: 2721MB (2853273600 bytes) starts at local address 0x0000000101000000
Buffer B: 2721MB (2853273600 bytes) starts at local address 0x00000001ab118000

Running 2 test sequences... (CTRL-C to quit)

Test sequence 1 of 2:

Running tests on full 5442MB region...
Stuck Address : ok
Linear PRN : ok
Running comparison tests using 2721MB buffers...
Random Value :

FAILURE! Data mismatch at local BUFA address 0x000000019146eb80, BUFB address 0x000000023b586b80
BUFA Data: 0x7fab2e5d631ddbfe, BUFB Data: 0x7faf2e5d631ddbfe

Compare XOR :

FAILURE! Data mismatch at local BUFA address 0x000000019146eb80, BUFB address 0x000000023b586b80
BUFA Data: 0xae164f1d9463727b, BUFB Data: 0xae124f1d9463727b

Compare SUB :

FAILURE! Data mismatch at local BUFA address 0x000000019146eb80, BUFB address 0x000000023b586b80
BUFA Data: 0x30bb2e9eeb63bb2c, BUFB Data: 0x30b72e9eeb63bb2c

Compare MUL :

FAILURE! Data mismatch at local BUFA address 0x000000019146eb80, BUFB address 0x000000023b586b80
BUFA Data: 0x25e3dba234e64dc8, BUFB Data: 0x7d8bdba234e64dc8

Compare DIV :

FAILURE! Data mismatch at local BUFA address 0x000000019146eb80, BUFB address 0x000000023b586b80
BUFA Data: 0x0000000000000000, BUFB Data: 0x0000000000000001

Compare OR : ok
Compare AND : ok
Sequential Increment: ok
Solid Bits : ok
Block Sequential : ok
Checkerboard : ok
Bit Spread : ok
Bit Flip : ok
Walking Ones : ok
Walking Zeroes : ok

Test sequence 2 of 2:

Running tests on full 5442MB region...
Stuck Address : ok
Linear PRN : ok
Running comparison tests using 2721MB buffers...
Random Value : ok
Compare XOR : ok
Compare SUB : ok
Compare MUL : ok
Compare DIV : ok
Compare OR : ok
Compare AND : ok
Sequential Increment: ok
Solid Bits : ok
Block Sequential : ok
Checkerboard : ok
Bit Spread : ok
Bit Flip : testing 132 of 512

FAILURE! Data mismatch at local BUFA address 0x000000015d145950, BUFB address 0x000000020725d950
BUFA Data: 0x0000000000210000, BUFB Data: 0x0000000000010000

Walking Ones : testing 22 of 128

FAILURE! Data mismatch at local BUFA address 0x000000015d145950, BUFB address 0x000000020725d950
BUFA Data: 0xffffffffffffffff, BUFB Data: 0xffffffffffdfffff

Walking Zeroes : testing 1 of 128

FAILURE! Data mismatch at local BUFA address 0x000000015d145950, BUFB address 0x000000020725d950
BUFA Data: 0x0000000000200001, BUFB Data: 0x0000000000000001


*** Memory Test Failed *** Please check transcript for details.
Execution time: 8020 seconds.



- An Update - Apple Hardware Tests claim that all units are working correctly. However, I had been informed to take these with a pinch of salt.

- Mem Test now showing a pass on the test but I appear to be having some hangups still.

- It has been raised that the Mem test above displays only 5442 MB of available memory - Why?

02-29-2012, 03:23 PM

If you are not running in Single User mode, does that mean you have the GUI running? If so, your test case is invalid and you SHOULD be running in single user mode to ensure that noone else is using the memory.

The program is doing a series of memory tests and is working on the assumption that it's the only one talking to the memory throughout the test. Not being in single user mode makes it unlikely that this is the case..

02-29-2012, 03:33 PM

I am glad someone was able to answer this as again some confusion elsewhere - The test is running in single user mode as we speak and currently is displaying its 7428MB of available RAM. I will let you know the results.



Initially, I was given a GUI for MemTest, a thing called ReMem or a word similar to that, which I was told negated the use for single user mode boot.

02-29-2012, 03:37 PM

+1. You can not do an accurate memory test unless the testing is done giving full control to the program. That can only be accomplished in single user mode.

There are several memory testing programs which will reboot the machine for you to ensure full control during the test, however, they are not free.

02-29-2012, 03:39 PM

I was going to also comment that you were losing some of the 8GB of memory since you only seemed to be seeing about 5.3G in the application, but seeing 7428MB now is encouraging..

02-29-2012, 03:49 PM

Thanks for a quick ultimate opinion, I will post the results once the test has completed (in 13551354262462 Hours..)

03-01-2012, 06:36 PM

Conclusion was that it now passed Mem Test twice in a row, thanks for all the help guys.

03-12-2012, 08:00 PM

To once again resurrect this topic - It would appear the Macbook Pro in question is definitely having more hangups than it used to when it had its original 4GB of RAM.


Consequently, I am still not convinced that the RAM is working correctly, and due to this being the only thing that has changed it from a working to lesser-well working machine I can only assume this is the issue.

03-12-2012, 08:26 PM

If you still have the original modules, pull the new ones and put the originals back in. Then ask for a RMA for the 8 GB from the seller and have them send you new modules or get a refund and buy the memory elsewhere.