Ram upgrade Macbook Pro 15" MID 2012

Macs are picky about RAM. "Just any RAM" will disappoint. Best RAM results are from Other World Computing (already mentioned) or Crucial.com. I won't buy Mac RAM from any other source.

However, why do you want to install RAM? My 2012 Macbook Pro runs macOS 10.14 fine on 8GB RAM. Too often, people ask here about increasing RAM because their computer feels too slow. In that case, the problem is not RAM but usually a slow factory mechanical hard drive. If the HD is the bottleneck, no amount of RAM will fix that, so you would be wasting money.

Simple yes or no scan:

• Is the computer slow to fully boot?
• Are apps slow to launch?
• Once apps launch, do they seem to perform OK

If your give three "yes" answers, chances of your having a RAM problem are very small.

So please let us know the reason you feel you need to add RAM.

The correct spec is: PC12800 DDR3L 1600MHz SO-DIMM from: https://eshop.macsales.com/item/OWC/1600DDR3S08S/

Official max RAM is 8GB; with compatible larger modules you can do up to 16GB RAM. To get to 16GB, I cannot recommend any vendors other than the two previous referenced.

You can search compatible RAM at the OWC site.