iMac late 2013 Memory failure !

[IA64]

I tried Apple Diagnostic tests today out of curiosity for the first time and got an Error PPM003 related to faulty memory module.

I never experienced any crash or panic. Boot time is 7 seconds and system is really smooth.

I have 32GB installed of RAM but I am not sure which one is faulty.

How can I find out which one ? I guess it's a dual channel so not possible to test them one by one.

Any hint please ?

 

[IA64]

So I tested 2 stick or RAMs and no errors found.

I tested the other 2 sticks and no errors found.

I installed the 4 sticks and tested again, now I have memory failure.

Does it mean the motherboard is defective ?

 

[troy14]

Did you test them one by one? I wouldn't test two at a time. Maybe test one by one in each different slot. Time consuming, absolutely. Or take it in to Apple.

 

[IA64]

Did you test them one by one? I wouldn't test two at a time. Maybe test one by one in each different slot. Time consuming, absolutely. Or take it in to Apple.

OK but what would be different ?

 

[nrubenstein]

OK but what would be different ?

Is the RAM all matching spec? Post a pic showing the labels on all four modules.

 

[IA64]

Is the RAM all matching spec? Post a pic showing the labels on all four modules.

 

[IA64]

Anyone ?

 

[IA64]

Last bump ? come one guys.

 

[WilliamG]

Last bump ? come one guys.

Try with 3 sticks in there. Try slots 1, 2, 3, and then 2, 3, 4. That would help narrow it down to socket issue or not.

 

[Chippy99]

4 sticks is always more difficult to drive than 2 sticks and any marginal problems in terms of compatibility or quality will often show up with 4 sticks and not with 2. CL9 is faster than Apple's regular specs as well - but you knew that. 4 sticks at CL9 is pushing it, and instability like this is not uncommon.

Your only option is to return all the memory and start again with 4 new sticks imho. And if you can try a different brand altogether, I'd do that. Is CL9 really that important to you? I'll bet it's not noticeably faster unless specifically benchmarking it. 4 stick at CL10 or CL11 would be a lot more likely to be stable.

 

[IA64]

4 sticks is always more difficult to drive than 2 sticks and any marginal problems in terms of compatibility or quality will often show up with 4 sticks and not with 2. CL9 is faster than Apple's regular specs as well - but you knew that. 4 sticks at CL9 is pushing it, and instability like this is not uncommon.

Your only option is to return all the memory and start again with 4 new sticks imho. And if you can try a different brand altogether, I'd do that. Is CL9 really that important to you? I'll bet it's not noticeably faster unless specifically benchmarking it. 4 stick at CL10 or CL11 would be a lot more likely to be stable.

Well I purchased the RAMs last year and never had any problem when I run memtest under OSX in single user mode.

Now suddenly it's displaying errors. Even with 32GB installed, If i run memtest 16000 ( 16GB split into 8 GBs ), it doesn't show errors. Only when I test the full memory available.


Also if it's returning errors, why I have never had any single crash sine more than 11 months ? Im puzzled.

 

[Chippy99]

Well I purchased the RAMs last year and never had any problem when I run memtest under OSX in single user mode.

Now suddenly it's displaying errors. Even with 32GB installed, If i run memtest 16000 ( 16GB split into 8 GBs ), it doesn't show errors. Only when I test the full memory available.


Also if it's returning errors, why I have never had any single crash sine more than 11 months ? Im puzzled.

I'm not at all surprised. As I say, compatibility is not a boolean thing. Things can be marginal and only show up is certain circumstances. 4 sticks puts much more load on the memory controller and it's obviously not able to drive all sticks at those timings with complete reliability.

As to why it doesn't cause errors in OS X, well when you run things like Memtest and Apple's diagnostics, they stress the hardware much more. It's very common for computers to be stable in normal use but to fail Memtest (or Prime95 for that matter).