MacBook Mid-2010 Polycarbonate Unibody not recognising 8GB RAM

[Marmotta]

I've installed an 8GB PC8500 DDR3 stick of RAM in my MacBook, but it's only showing up as 4GB. Any ideas why? I've run memtest86 in it and it only shows up as 4GB as well.

I have read of 2010 MacBooks showing certain 8GB sticks as 4GB, but does anyone know if it would then show up in memtest as 4GB as well? It was a used module, so I'm thinking perhaps the label had been swapped on it....

 

[keysofanxiety]

That model recognises up to 8GB RAM but not 8GB DIMMs. So you’ll need 2x4GB 1066MHz SODIMM to get the maximum 8GB.

 

[Marmotta]

That model recognises up to 8GB RAM but not 8GB DIMMs. So you’ll need 2x4GB 1066MHz SODIMM to get the maximum 8GB.

Everything I've read suggests the model (7,1) supports 16GB of RAM, but the previous polycarbonate model supported a maximum of 8GB.

I would settle for two 4GB sticks, but unfortunately one of the slots seems to be faulty.

 

[keysofanxiety]

Everything I've read suggests the model (7,1) supports 16GB of RAM, but the previous polycarbonate model supported a maximum of 8GB.

I would settle for two 4GB sticks, but unfortunately one of the slots seems to be faulty.

The MacBook Pro 7,1 supports 16GB but the MacBook 7,1 is 8GB.

 

[DeltaMac]

According to Mactracker app, also Macsales (OWC) (They test this stuff to make sure it works), and DataMemorySystems (also test their upgrades), the Macbook7,1 will support up to 16GB RAM installed.
So, assuming that the OP has up-to-date firmware (and assuming that even the "good" slot is fully functioning) the 2010 MacBook should support a single 8GB stick (also assuming that stick is within the supported specs)

@Marmotta: If you don't have success with a single 8GB stick, and it was a used stick, but only recognized as 4GB, you may be correct about a swapped label. Try a different 8GB stick, from a usually-respected brand such as OWC or Crucial.

The MacBook, and some Macbook Pros are often quite finicky about the RAM, and "not quite spec, but should work" sometimes does not.

 

[EugW]

Is your firmware up to date?

 

[DeltaMac]

Here's a support page that will help you decide if your firmware is current.

 

[Marmotta]

I believe I'm running the latest firmware - at least it won't let me install the .pkg files linked on the support page.

I checked the RAM part number and it's showing as 0x393930353432382D3030352E4130324C4620, which seems to show up as a 4GB Kingston module. Apple Hardware Test and MemTest86 both show it as being 4GB as well. The label does appear to say 8GB, but it seems the RAM was sold as a 8GB (2x4GB) kit, so that may be why the seller thought it was 8GB, rather than swapping the label. I have tried googling the memory chips on the RAM to see whether they're 256MB or 512MB (16 in total), but I couldn't find anything reliable.

I wish I had a reputable stick to test (or even an older Windows laptop I could try the RAM with), but unfortunately 8GB PC8500 modules don't grow on trees.

Thanks to everyone for the help so far.

 

[DeltaMac]

You are correct. You have a single stick that is 4GB, part of an 8GB kit.
Some vendors sell memory exactly that way. 8GB as a kit of two sticks.
So, yes the RAM is 8GB, which is 2 x 4GB sticks, installed as a pair to give you the total of 8GB.
And, that leaves YOU on the short end if you have one bad slot. One stick gives you 4GB, because it is only the one stick.
And, if the sticks are the wrong configuration, you only get 8GB in certain motherboards, because the motherboard chipset has to accept the combined (matched) pair of 4GB sticks. Otherwise, you don't get full speed, or you might get memory errors. That's not really a problem on a Mac, but the pair to give 8GB total is kind of misleading.
And, you are still stuck because you can only use one stick.
Most of those "kits" will tell you they are 2x4GB sticks somewhere in the description, so you get to be careful, if you only want the single 8GB stick. (When you see the word "Kit", that's usually your clue that it is a pair (or more) of sticks.)