RAM DIMM(s) or DIMM Slot(s) - Test Fail #4

[iamBATMAN]

Was hoping someone would be able to decipher this better than I can.

13inch Macbook Pro - If any other information is required, ask.

[iamBATMAN]

Reran the tests with different RAM modules - no errors. Placed the same RAM modules back in - no errors.

I can't determine what's failing, if it fails intermittently. This makes it impossible to do process of elimination being that I can not successfully replicate or produce the errors.

[David (PassMark)]

Looks like the RAM might be bad. But only a couple of bits were wrong in 3 hours of testing. So it isn't a very dramatic failure.

Is the machine stable in normal use?

[iamBATMAN]

Looks like the RAM might be bad. But only a couple of bits were wrong in 3 hours of testing. So it isn't a very dramatic failure.

Is the machine stable in normal use?

Machine is stable during use and only intermittently fails to POST - giving off three audible beeps in recession indicating RAM failure.

To fix the issue of it failing to POST, the RAM is reseated. This is a temporary fix, however, until the next time it fails to POST.

[David (PassMark)]

Are there two sticks?
Can you try one stick at a time & try it in each slot to work out via trial and error which stick or slot might be bad.

[iamBATMAN]

Are there two sticks?
Can you try one stick at a time & try it in each slot to work out via trial and error which stick or slot might be bad.

Yeap, two DIMMs. I can try to do process of elimination, however, with the issue being intermittent it's likely going to be extremely difficult to get MemTest to report errors. It's currently running with both DIMMs back in there, on pass 4 of 4, with no errors reported.

[David (PassMark)]

It is unlikely to be the software that is intermittent.

It could be that it really is totally random. For example external electromagnetic interference, or a dirty power supply. Or it could just bit that the problem is a real RAM problem, but the failure only occurs very rarely.

If you have other RAM available, I would suggest swapping out both the sticks and then see if you continue to have POST problems over the next few weeks.

[iamBATMAN]

It is unlikely to be the software that is intermittent.

It could be that it really is totally random. For example external electromagnetic interference, or a dirty power supply. Or it could just bit that the problem is a real RAM problem, but the failure only occurs very rarely.

If you have other RAM available, I would suggest swapping out both the sticks and then see if you continue to have POST problems over the next few weeks.

I would totally do that, except the unit we're talking about it a customer's and not mine. I kinda have to figure out what the underlying problem is and fix it, by tomorrow.

[David (PassMark)]

Can you take the suspected bad RAM and stick it in another (known to be working) machine and run tests on it there in conjunction with testing the customers machine with new RAM. If you do this both at the same time you might reach some conclusion before tomorrow.

[iamBATMAN]

Can you take the suspected bad RAM and stick it in another (known to be working) machine and run tests on it there in conjunction with testing the customers machine with new RAM. If you do this both at the same time you might reach some conclusion before tomorrow.

Great suggestion, I'm going to attempt this and see what results I get.

[iamBATMAN]

Great suggestion, I'm going to attempt this and see what results I get.

After a thirty (30) test loop, no errors reported on either machine testing the RAM modules.

[David (PassMark)]

Normally it would be a good thing that there are no errors.
However in this case it just means the POST problem you have is more subtle / obscure / intermittent. Could be temperature related, an EMI issue, power supply issues, a bad CPU, bad Motherboard, bad firmware chip that holds the BIOS, intermittent connection on the RAM slot susceptible to vibration, etc...

[iamBATMAN]

Normally it would be a good thing that there are no errors.
However in this case it just means the POST problem you have is more subtle / obscure / intermittent. Could be temperature related, an EMI issue, power supply issues, a bad CPU, bad Motherboard, bad firmware chip that holds the BIOS, intermittent connection on the RAM slot susceptible to vibration, etc...

Customer had 4GB of RAM in i5 2012 Macbook Pro - upgraded him to 8GB of RAM being that he's going to be entering college this fall for graphic design. Going to see if the new RAM runs into any issues - if it does, have the MLB on hand to replace. Although not my ideal solution, customer was okay with this.