MacBook Pro mid-2012 ram bank issue

Attempting to upgrade memory on mid-2012 MBP with core i7 processor. The oem config was two banks with 4gb (1600DDR3) in each. Aiming to put 8gb in each bank. Removed both original memory moduels. Inserted new ones. Powered on and met with beep every seven seconds or so; a single beep every seven seconds. I can remove one module, leaving one bank empty, and it powers up and runs just fine recognizing 8g ram. I can do this with each of the new modules, and in each of the banks. (So both modules seem to be fine; and each of the banks seem to be fine). But I can't get it to power up with both modules properly seated in each bank.

Worse yet, I cannot seem to get back to where it all started. Meaning, I have tried to simply re-insert the original two ram modules in each bank, and the same issue occurs - it will only boot with one module in one bank, and switching each module to the other bank did not fix the issue either. Both modules work just fine on their own, in either bank0 or bank1; showing 4g installed ram. But I cannot get the computer to boot with two modules installed; despite the fact that the computer worked just fine with the original two 4g modules, for a total of 8g ram, before I started this whole upgrade journey.

Is there something simple I'm missing here? This MBP should accept up to 16g with both banks populated; but now, I can't even go back to where I was this morning.

Give this a try:

- Install the original RAM (2 x 4gig) in both banks.
- Shut down the computer.
- Reboot the computer following the SMC Reset procedure in this link:

https://support.apple.com/en-us/HT201295

Hopefully all goes well. If so...then remove the original RAM and install the new RAM (2 x 8gig).

HTH,

- Nick

Trust you did not purchase the modules from eBay or a PC shop.

Macs are very fussy about memory specifications. OWC and Crucial recommended and here is the correct spec'd memory:-


https://eshop.macsales.com/item/OWC/1600DDR3S16P/

Give this a try:

Click to expand...

+1.

Hopefully all goes well. If so...then remove the original RAM and install the new RAM (2 x 8gig).

Click to expand...

And maybe even repeat the above SMC Reset suggestion if needed.




- Patrick
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Having read a few forums and other info, I tried PRAM resets and SMC resets. it does not seem to affect the issue. I understand where harryb2448 is coming from on being sure it is the exact spec on the new RAM; but the crazy issue is ... even if the new RAM isn't exactly right, or the MBP is finnicky with new RAM ... I cannot even return to the previoust status quo - the original RAM modules re-inserted in both banks will not boot up. AND, it's not a question of a bad socket/bank/logic-board because the MBP will boot with each of the original modules in either one of the banks: bank0 works just great with the original 4gb module in it (or with the OTHER original 4gb module in it); or with a new crucial 8gb module in it; and bank1 works just great with with the original 4gb module in it (or with the other original 4gb module in it; or with a new crucial 8gb module in it). But, for whatever whacky reason I can't seem to get both bank0 and bank1 to boot the MBP with the original 4gb RAM in each or with the new 8gb in each bank.

tkmooney said:

Having read a few forums and other info, I tried PRAM resets and SMC resets. it does not seem to affect the issue. I understand where harryb2448 is coming from on being sure it is the exact spec on the new RAM; but the crazy issue is ... even if the new RAM isn't exactly right, or the MBP is finnicky with new RAM ... I cannot even return to the previoust status quo - the original RAM modules re-inserted in both banks will not boot up. AND, it's not a question of a bad socket/bank/logic-board because the MBP will boot with each of the original modules in either one of the banks: bank0 works just great with the original 4gb module in it (or with the OTHER original 4gb module in it); or with a new crucial 8gb module in it; and bank1 works just great with with the original 4gb module in it (or with the other original 4gb module in it; or with a new crucial 8gb module in it). But, for whatever whacky reason I can't seem to get both bank0 and bank1 to boot the MBP with the original 4gb RAM in each or with the new 8gb in each bank.

Click to expand...

Yes...aware of all this from post #1. Why I focused on non-RAM, non-logic board, non-socket related fixes.

If PRAM & SMC Rests do not help...other thought's are:

- Is the RAM being fully inserted properly?
- Is there any debris in the RAM slots?

I realize that both these are probably not the issue...since you seem to be able to get a single RAM stick to work in each slot. But got to mention them for completness sake.

Last thought is to 100% eliminate the possibility of a software/OS related issue. To test this...boot the computer from a different storage device...preferably with only a fresh install of the macOS (no other 3rd party apps).

- Nick

thanks, Nick. I don’t mean to re-state earlier stuff except to try to explain where I am, and have come from; I am in the process of doing a clean install to a new SSD, so I can try out your suggestion soon.

But, for whatever whacky reason I can't seem to get both bank0 and bank1 to boot the MBP with the original 4gb RAM in each or with the new 8gb in each bank.

Click to expand...

I must agree and it seems bizarre to me, especially with the original RAM modules not working, but it seems you are not alone with the problem according to this:
https://www.ifixit.com/Answers/View/327569/Issues+with+bottom+RAM-slot+MBP+2012

It seems that a loose solder joint may be the cause, but that still doesn't really make sense to me.
But do make note of the comment there for a possible fix:

Try this: We've had reports that loosening the RAM bracket holder screws a quarter turn each has worked.

Click to expand...

Sure worth a try!!!

BTW what lights and sequence are you seeing wherever the possibly flashing lights are???

At least I gather it will run with a single 8GB module which is not bad for most users use.

And as it does work apparently, that sure doesn't account for any loose module solder joint in my brain's logistics!!!

Scratching head here… but try the RAM bracket tightening screw trick or some of the other suggestions ….

Here's hoping!!!




- Patrick
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I agree with what Patrick suggested. I have seen several situations where the ram bracket holders had to either be tightened down or loosened. Worth a try if you don't mind taking your machine apart.

pigoo3 said:

Last thought is to 100% eliminate the possibility of a software/OS related issue. To test this...boot the computer from a different storage device...preferably with only a fresh install of the macOS (no other 3rd party apps).

- Nick

Click to expand...

After installing my new SSD to replace the original hard drive, and a clean install of the OS, problem solved.
Thanks for all the suggestions. weird, tho...

problem solved.
Thanks for all the suggestions. weird, tho...

Click to expand...

Weird is an understatement, but good news. Sand let's hope it lasts.

Did you happen to check the tightness/looseness of the memory holder screws???




- Patrick
======

tkmooney said:

After installing my new SSD to replace the original hard drive, and a clean install of the OS, problem solved.

Click to expand...

Sounds like it was a software/OS issue. After all of the hardware troubleshooting you did...and the different permutations of the RAM installed...I was thinking if it isn't a software/OS thing...we would REALLY be stuck for further ideas!

Congrats!

- Nick