2012 ram issue

[misterminibus]

I’ve treated myself to a new 2.3 ghz i7 and I’ve fitted an ssd and upgraded from 8GB of ram to 16 but it’s beeping 3 times, I’ve put the old ram back in and it’s still beeping. When I use one 8GB stick in the bottom Port only it works, I can swap the sticks and the other 8GB works on its own too, they are new crucial sticks so it’s only using 8GB at present. Has anyone got any ideas how to fix this?

 

[m1maverick]

I’ve treated myself to a new 2.3 ghz i7 and I’ve fitted an ssd and upgraded from 8GB of ram to 16 but it’s beeping 3 times, I’ve put the old ram back in and it’s still beeping. When I use one 8GB stick in the bottom Port only it works, I can swap the sticks and the other 8GB works on its own too, they are new crucial sticks so it’s only using 8GB at present. Has anyone got any ideas how to fix this?

Can you provide the exact model of the system you're experiencing the problem with?

Was the original 8GB 2 x 4GB or 1 x 8GB?

 

[misterminibus]

 

[misterminibus]

Sorry I forgot to post it, I can't seem to get it to read 16GB

 

[Amethyst1]

When I use one 8GB stick in the bottom Port only it works, I can swap the sticks and the other 8GB works on its own too […]

So the top memory slot isn’t playing ball?

 

[misterminibus]

Both slots work with 1 8gb stick and then when I swap for the other stick, again both slots work.
I can put any 8gb stick in any slot and it works but when I put both 8gb sticks in and reboot it beeps 3 times

 

[Nguyen Duc Hieu]

Both slots work with 1 8gb stick and then when I swap for the other stick, again both slots work.
I can put any 8gb stick in any slot and it works but when I put both 8gb sticks in and reboot it beeps 3 times

Both of your RAM sticks are identical?
Can you post a side-by-side photo of them here?
At this time, the only issue we can think of, is different RAM type. (Bus speed or Voltage, or even ECC ram. Some DDR3 SODIMM also have ECC chip, according to a post I read recently)

 

[paardenkapper]

I'd just get a second stick like you already bought and keep the other as a spare. I'm sure it's down to the memory density.

I never had problems with Crucial RAM - you can find it for cheap at amazon.

 

[misterminibus]

Both of your RAM sticks are identical?
Can you post a side-by-side photo of them here?
At this time, the only issue we can think of, is different RAM type. (Bus speed or Voltage, or even ECC ram. Some DDR3 SODIMM also have ECC chip, according to a post I read recently)

Yes they were bought together

 

[misterminibus]

The seller (ebay) is saying that my mac mustn't be compatible with 16GB can anyone tell me first hand if a 2012 A1286 can take 16GB please?

 

[B S Magnet]

The seller (ebay) is saying that my mac mustn't be compatible with 16GB can anyone tell me first hand if a 2012 A1286 can take 16GB please?

Yes. It can. You can send them to Everymac’s specs.

But even if that info isn’t enough, my late 2011 A1278 (the same architecture of the late 2011 A1286, and this architecture was tweaked only slightly for the mid-2012 models to update to Ivy Bridge and USB 3.0) is running, as we speak, on 16GB RAM (at 1333MHz, not 1600MHz) without a hitch.

That all said, have you A) been able to run a low-level memtest on each of the RAM sticks, to verify they check out okay, and B) have you been able to given the top RAM slot a close visual inspection (to make sure there isn’t some minor debris obstructing one of the connection points which found its way there as you were pulling out your original RAM)?

SIGNIFICANT UPDATE: The pics of the two sticks of Crucial RAM you shared above are DDR3. Look at your OEM RAM sticks. Check whether they’re DDR3 or DDR3L. This is relevant if the system expects DDR3L (which runs at 1.35V) but the RAM only operates at 1.50V. Whereas throwing in DDR3L RAM into a system which came out when all RAM ran at 1.50V will work find (as the DDR3L logic will step up to 1.50V), a system designed for DDR3L (1.35V) RAM is not designed to accept RAM which only runs at 1.50V (i.e., DDR3). It does surprise me that one stick works, but I have a sneaking suspicion that the original RAM from your MBP was/is DDR3L. If this is the case, you will need to probably return these in exchange for DDR3L, which may or may not be the same price.

The specs listed by Everymac suggest the mid-2012 runs DDR3L RAM, not DDR3.

Here’s an additional, more technical discussion about what changed with the Ivy Bridge update. It appears 1.35V — something a DDR3L can do, but not a DDR3 — is what the system requires for RAM to function reliably (i.e., being able to use both slots without issues).

 

[theMarble]

The specs listed by Everymac suggest the mid-2012 runs DDR3L RAM, not DDR3.

The 2012 Retina uses DDR3L, but the unibody 2012's (both 13" and 15") use standard DDR3.

 

[B S Magnet]

The 2012 Retina uses DDR3L, but the unibody 2012's (both 13" and 15") use standard DDR3.

Do you have technical references which verify this?


EDIT: Per the Intel spec sheet on the i7-3820QM (the processor in the 2.7GHz i7 model here), it calls for DDR3/L/RS (DDR3L-RS) modules. Additional citations, including Intel’s testing validation of extant vendors’ RAM for Ivy Bridge mobile processors note that mobile variants of the Ivy Bridge processor (versus desktop variants) are designed for DDR3L sticks.

Unfortunately, I don’t have an Ivy Bridge MBP handy, or else I’d have probably tested all this by now.

 

[theMarble]

Do you have technical references which verify this?

I'm going off of what both Apple Support and Mactracker say. Also, in my time opening up and repairing these, I've personally never seen one with DDR3L (a 2012 unibody that is). It's possible that they are cross-compatible and some shipped with DDR3L though.

 

[B S Magnet]

Paging @dosdude1 (sorry to have to pull you into this, but if there’s anyone on here who’d know and have the final, definitive word)…