Both tags ram (x7) and memory (x69) deal with the same thing (or rather the questions tagged thus do). Strictly spoken, RAM is part of memory -- but in daily use, they are used synonymously. So I'd suggest we do the same, and merge the 7 questions "ram" into "memory", plus making "ram" a synonym to "memory".
All 69 questions with memory talk about RAM and not internal storage? Seems unlikely, I've seen them confused more often than not (sadly). If anything I'd merge the reverse direction for clarity.
memory is simply not a great tag. It invites people to misuse it, and before performing the merge I ended up retagging ~20 questions that were using memory to refer to their internal storage (which we specifically have internal-storage for). Therefore, I think that making ram the master tag is the better idea.
There's no difference between RAM and memory (in or out the questions)
RAM is sometimes called "memory" for short which further complicates the issue. RAM is a computer chip that assists in speed of the computer that is measured in Megabytes (MB) or Gigabyte (GB) depending on the size of the chip. When a user chooses to open a file, the computer must put that information somewhere to be able to access it. It writes the file temporarily to the RAM for easy access. RAM also temporarily saves files that are currently being worked on.
So I agree with you that they should be merged.