Updating apple memory
Of course if you have not come close to using available memory and are strictly constrained by processing speed(perhaps you're encoding a video or something) then yes, CPU upgrade is the way to go.
For general use PCs "back in the day" I used to buy cheap Celerons at a lower mhz then just put a boatload of RAM in there.
I knew this route was cheaper, but I didn’t realise just how simple it actually was to do – I was gearing up for a surgical procedure in my head but the reality is its super simple to do yourself. This process — updating from 8GB to 32GB – is so simple anybody can do it.
500RAW files from the EOS 6D only use about 4GB of RAM, leaving the other files on virtual memory! One needs to understand where their bottlenecks are in their system before making the decision to do either.
If you're at the point where you are hitting swap memory and have effectively run out of physical then it makes much more sense to upgrade memory.
Or, buy a decent PC and quit the i Crap i Bullcrap thing! *EDIT* Oh and just in case you people don't know, the ability of RAW processing and image processing is on the Processor!!
RAM will only increase the amount of files you can load at once.