Same 4MEM/9/40000000 , but different aka (hopefully) the complete guide to this error code and changing RAM

Question

Hello world,
finally, after having been reading here for years I decided to break silence and join the most venerable Apple discussions community!
First of all, I'm no native speaker, so if I at one point don't express myself correctly, I'm sorry. If you don't understand please ask what exactly I meant since it's very important that we know exactly what each one of us is talking about, thank you.
Important, too:
I know there are a lot of posts with this topic and I sifted through a lot of them but none of them captures exactly what my problem or rather my questions are and unfortunately in a lot of them there is no real feedback from the original poster how it all worked out or not. So, I intend this thread to be that one helpful thread which more or less concentrates the knowledge of the other threads, where people with similar problems can go to in future.
I ask one thing of you: Please DON'T answer with just one phrase à la "U got bad RAM, send it back" or "Contact Apple Customer Support Service whatever thingy" without explaining why this would be the only viable option (because I think it is not, at least at the moment).
All the questions I 'd like answered are green, for you to not lose track. I hope this becomes a good discussion so everyone of us can learn a lot!
Following problem:
Initial situation:       
My Computer: MacBookPro 8.2, early 2011, 15", 2,2 GHz i7; Mavericks 10.9.5    (yet without this bash fix but ¯\_(ツ)_/¯ )
       - Upgraded RAM from onboard 4 (2 x 2) GB to the "unofficially" possible 16 (2 x 8) GB 
Ordered RAM on Amazon.de with the right Specs: 204 pin DDR3 SO-DIMM (1333 MHz, PC3-10600S, CL9),
Manufacturer: CSX (http://www.csx-memory.com , while it's maybe not the most renown seller, it was described on another website as reliable )
    HERE (hope the link doesn't  change):               http://www.amazon.de/gp/product/B0084SH6WA/ref=oh_aui_detailpage_o01_s00?ie=UTF8 &psc=1
       - Installed it, booted Mac without problem, what does System Profiler say? I have full 16 GB   1600 MHz   Memory installed
- Obviously sent me the "wrong" RAM (or can System Profiler be wrong??), funny thing: It works,
     --> after a LOT of research checked here http://guides.macrumors.com/Buying_RAM      my i7 is 2720QM, so supports it, lucky me
   Btw, if i go to About this Mac > more information > memory,  the Text there even says it can hold 1600 MHz, has this been written there like this all along?!
- Which RAM do I have installed exactly now? since the sticker on it showed the originally ordered Specs.., moreover how do I determine the CAS latency of my installed RAM?
Crashes:
Didn't really have any, except..... well,  
- In some instances Firefox (I think 32.02. or sth., the latest Version at this moment) reproduceably keeps crashing, for example right now, can't even start it,  that's why I can't tell you the exact version, maybe I edit that later. Safari so far hasn't crashed.
- Once I had a System Crash, but it happened when I wanted to reboot after updating the firmware of a hooked on external WD drive to be usable again as time machine backup volume under mavericks (without endangering my data).
The RAM seems to work fine; for example when I was doing a long overdue backup of 77GB on said drive, Activity Monitor showed a RAM Usage of  15,99 GB and nothing crashed. Only the fans were powering at some point but i thought that normal..
- Actually produced two more Crashes when trying to run Apple Hardware Test (AHT), the one on the second disc that originally came with my Computer (probably made for OS 10.6.x    x= 6 or sth., don't remember which version my MBP was shipped with), which leads to
Tests:
Memtest86
- I put Memtest86 v.5.01 on a USB Stick and bootet from that and let it test "the whole" RAM 
(btw Do you know how you can put the bootable USB image of Memtest only to one (of a few) partition of my 32 GB USB Stick? The instructions (command line stuff) only let me put it on the whole Stick which makes it otherwise useless as a volume; ok here I'm not sure if I'm using the correct technical terms....)
- I let Memtest86 do 3 and a half passes with one pass consisting of 10 different tests, so it took over 8 hours! 
--> RESULT:   0   (in words: zero)  ERRORS,         
--> That is why I think my RAM is ok, because I think (think NB, don't know) Memtest86 does good testing,or do you know      better?
AHT
- After that, out of curiosity, I tried to run AHT from the DVD with said results, then I ran AHT (also called Apple Diagnostics under Mavericks) from the Internet, this worked, but produced the famous 4MEM/9/40000000 Error Code,
first one for example was: 4MEM/9/40000000: 0x8477df98, the last part after the colon is variable, but stays the same in one instance, i.e. if you repeat the AHT directly. If you restart the Computer an rerun the test then it changes, e.g. some other it showed 0x84770a18
- I did the short and the extended version, it took ca. 2-3  and 16 min respectively till producing the Error Code (only 1 at a time)
- Did it 4 times or so; once in short/simple version it showed no error, the rest the 4MEM/9 s.
some example of a simple test, results taken out of the System Profiler Window (fehlgeschlagen= failed):
Apple Diagnostics:
The usual self test on start up is always passed (bestanden), see for example:
What other than bad RAM can 4MEM/9/40000000 mean? I hope there are a few tech and computer savvy people around this place who know what they are talking about and can give me a good answer, or at least help to narrow it down. Actually I also think, the RAM sticks are not loose, but before I screw open my MBP again I would like to explore the other possibilities.
Is it probable that this Error Code has got sth. to do with me installing a) 16 GB of b) 1600 MHz RAM, or maybe with CAS Latency (i don't know the actual CL of this RAM)? and if so, is it only because some Apple Programmer/Developer/Technician wrote some values in a list on the System Level, so it doesn't accept RAM it would normally work with?? If it works fine and is faster, why change it?
Final Words:
I repeat, apart from the Firefox crashes, my Mac seems to be working fine, at least I don't notice anything, (well, that disk utility and System Profiler (or whatever it's called nowadays) sometimes take time to start up is nothing special i think, is it?)
But now I'm scared that perhaps there could be a future danger for my computer I do not foresee...I hope you can at least exclude that.
So I'd rather spend my time starting a discussion here with people who don't have to abide by some corporate policy (right?) than having the hassle of repeatedly screwing my Mac open and shut  and doing expensive calls with all the companies involved who won't tell me anything more in depth than "we have to send it there, do more tests and you get it back then".
I hope that this thread won't rot in the wastelands of unanswered posts and that maybe all the people who take part in it learn sth. and all the people seeking help in future will find it here.
Thanks for your patience!
Waiting for your greatly appreciated answers,
MuddyMic
PS: Why is there no category Hardware, Components, RAM or sth similar? Not sure if it fits in Ports and Interfaces so I put it under Using a MBP

Answer 1

Hello world,
finally, after having been reading here for years I decided to break silence and join the most venerable Apple discussions community!
First of all, I'm no native speaker, so if I at one point don't express myself correctly, I'm sorry. If you don't understand please ask what exactly I meant since it's very important that we know exactly what each one of us is talking about, thank you.
Important, too:
I know there are a lot of posts with this topic and I sifted through a lot of them but none of them captures exactly what my problem or rather my questions are and unfortunately in a lot of them there is no real feedback from the original poster how it all worked out or not. So, I intend this thread to be that one helpful thread which more or less concentrates the knowledge of the other threads, where people with similar problems can go to in future.
I ask one thing of you: Please DON'T answer with just one phrase à la "U got bad RAM, send it back" or "Contact Apple Customer Support Service whatever thingy" without explaining why this would be the only viable option (because I think it is not, at least at the moment).
All the questions I 'd like answered are green, for you to not lose track. I hope this becomes a good discussion so everyone of us can learn a lot!
Following problem:
Initial situation:       
My Computer: MacBookPro 8.2, early 2011, 15", 2,2 GHz i7; Mavericks 10.9.5    (yet without this bash fix but ¯\_(ツ)_/¯ )
       - Upgraded RAM from onboard 4 (2 x 2) GB to the "unofficially" possible 16 (2 x 8) GB 
Ordered RAM on Amazon.de with the right Specs: 204 pin DDR3 SO-DIMM (1333 MHz, PC3-10600S, CL9),
Manufacturer: CSX (http://www.csx-memory.com , while it's maybe not the most renown seller, it was described on another website as reliable )
    HERE (hope the link doesn't  change):               http://www.amazon.de/gp/product/B0084SH6WA/ref=oh_aui_detailpage_o01_s00?ie=UTF8 &psc=1
       - Installed it, booted Mac without problem, what does System Profiler say? I have full 16 GB   1600 MHz   Memory installed
- Obviously sent me the "wrong" RAM (or can System Profiler be wrong??), funny thing: It works,
     --> after a LOT of research checked here http://guides.macrumors.com/Buying_RAM      my i7 is 2720QM, so supports it, lucky me
   Btw, if i go to About this Mac > more information > memory,  the Text there even says it can hold 1600 MHz, has this been written there like this all along?!
- Which RAM do I have installed exactly now? since the sticker on it showed the originally ordered Specs.., moreover how do I determine the CAS latency of my installed RAM?
Crashes:
Didn't really have any, except..... well,  
- In some instances Firefox (I think 32.02. or sth., the latest Version at this moment) reproduceably keeps crashing, for example right now, can't even start it,  that's why I can't tell you the exact version, maybe I edit that later. Safari so far hasn't crashed.
- Once I had a System Crash, but it happened when I wanted to reboot after updating the firmware of a hooked on external WD drive to be usable again as time machine backup volume under mavericks (without endangering my data).
The RAM seems to work fine; for example when I was doing a long overdue backup of 77GB on said drive, Activity Monitor showed a RAM Usage of  15,99 GB and nothing crashed. Only the fans were powering at some point but i thought that normal..
- Actually produced two more Crashes when trying to run Apple Hardware Test (AHT), the one on the second disc that originally came with my Computer (probably made for OS 10.6.x    x= 6 or sth., don't remember which version my MBP was shipped with), which leads to
Tests:
Memtest86
- I put Memtest86 v.5.01 on a USB Stick and bootet from that and let it test "the whole" RAM 
(btw Do you know how you can put the bootable USB image of Memtest only to one (of a few) partition of my 32 GB USB Stick? The instructions (command line stuff) only let me put it on the whole Stick which makes it otherwise useless as a volume; ok here I'm not sure if I'm using the correct technical terms....)
- I let Memtest86 do 3 and a half passes with one pass consisting of 10 different tests, so it took over 8 hours! 
--> RESULT:   0   (in words: zero)  ERRORS,         
--> That is why I think my RAM is ok, because I think (think NB, don't know) Memtest86 does good testing,or do you know      better?
AHT
- After that, out of curiosity, I tried to run AHT from the DVD with said results, then I ran AHT (also called Apple Diagnostics under Mavericks) from the Internet, this worked, but produced the famous 4MEM/9/40000000 Error Code,
first one for example was: 4MEM/9/40000000: 0x8477df98, the last part after the colon is variable, but stays the same in one instance, i.e. if you repeat the AHT directly. If you restart the Computer an rerun the test then it changes, e.g. some other it showed 0x84770a18
- I did the short and the extended version, it took ca. 2-3  and 16 min respectively till producing the Error Code (only 1 at a time)
- Did it 4 times or so; once in short/simple version it showed no error, the rest the 4MEM/9 s.
some example of a simple test, results taken out of the System Profiler Window (fehlgeschlagen= failed):
Apple Diagnostics:
The usual self test on start up is always passed (bestanden), see for example:
What other than bad RAM can 4MEM/9/40000000 mean? I hope there are a few tech and computer savvy people around this place who know what they are talking about and can give me a good answer, or at least help to narrow it down. Actually I also think, the RAM sticks are not loose, but before I screw open my MBP again I would like to explore the other possibilities.
Is it probable that this Error Code has got sth. to do with me installing a) 16 GB of b) 1600 MHz RAM, or maybe with CAS Latency (i don't know the actual CL of this RAM)? and if so, is it only because some Apple Programmer/Developer/Technician wrote some values in a list on the System Level, so it doesn't accept RAM it would normally work with?? If it works fine and is faster, why change it?
Final Words:
I repeat, apart from the Firefox crashes, my Mac seems to be working fine, at least I don't notice anything, (well, that disk utility and System Profiler (or whatever it's called nowadays) sometimes take time to start up is nothing special i think, is it?)
But now I'm scared that perhaps there could be a future danger for my computer I do not foresee...I hope you can at least exclude that.
So I'd rather spend my time starting a discussion here with people who don't have to abide by some corporate policy (right?) than having the hassle of repeatedly screwing my Mac open and shut  and doing expensive calls with all the companies involved who won't tell me anything more in depth than "we have to send it there, do more tests and you get it back then".
I hope that this thread won't rot in the wastelands of unanswered posts and that maybe all the people who take part in it learn sth. and all the people seeking help in future will find it here.
Thanks for your patience!
Waiting for your greatly appreciated answers,
MuddyMic
PS: Why is there no category Hardware, Components, RAM or sth similar? Not sure if it fits in Ports and Interfaces so I put it under Using a MBP