paparazzo
Member
1. More RAM will never make your system faster unless the existing RAM is already being maxed out. If you aren't maxing out your 4GB then 16GB would have precisely zero effect.
2. Generally no; that 4GB is already placed into the (limited number of) memory slots, so you could only add on memory if there were unused slots. If your iMac has two slots and if that's the compatible set for you, you would have to take out the existing 4GB.
Ah, gotcha. My iMac actually does have four ram slots total with two of them free but it sounds like it'd be useless for me. Thanks for the input.