Do I need more memory on my iMac (Mid 2011)?

Question

First and for most I want to make sure that I'm addressing the correct problem that's why I am asking a question that appears to be asked by many people on here. I mainly use my imac 27" to produce music (I use Logic and a LOT of plugins and instruments) and well I always get the following message:
I hate it because I get it everytime Logic reaches a point where a lot of instruments and sounds come in (It's annoying and ruins my work flow). I usually just have logic and chrome open, bc I close everything else to help my situation.
I bought my iMac thinking it would be faster than any laptop and I now realize that it doesn't matter if it's a laptop or a desktop but rather the memory it has and other things included. Anyways what would all of you recommend? What would be most useful to change? Would it just be adding memory (increasing the 4GB)? Thanks for your time!!
<Image Edited By Host>

Answer 1

I would just like to add to what everyone else said about 4GB really not being enough for doing much of anything. Even Safari and Mail can easily run up to the limit.
If you are running up against the memory limit, your computer will start doing what is known as "thrashing". On an OS like iOS, too much memory simply causes running apps to be killed. On Windows and OSX, if you try to use more memory than what is available, the computer will start to use a disk cache as if it was memory. It will try to put the "older" items in memory to the disk. If you need to access that memory, the OS needs to load it back from disk. The problem is that the disk is about 20x or more slower than memory. When your computer is thrashing, it will seem like it is not working at all.
If you are not running against the memory limit, then adding more memory will do absolutely nothing to improve performance. If you are running against the limit, you will be amazed at how much faster your computer will run with the extra memory.
As far as adding memory goes, as others have said, you need to add them in matched pairs. Also as other have said, the 2011 iMac secretly supports 8GB ram cards. (check OWC at macsales.com and they will confirm).
My advice would be to buy two 8GB cards ($109 at OWC) and add them in addition to your two 4GB cards. That will give you a total of 20GB. 20GB is TONS of memory and I am 100% sure that should be plenty for you. More is almost definitely overkill. You could almost definitely get away with adding 2 4GB cards for $50 as well (this would triple the memory you currently have), but memory is getting really cheap, and is a great way to "future proof" your computer.
If you want to see what your computer is doing, try looking at "Activity Monitor". If you start it up, sort the processes by "Real Mem" and you can see which processes are using the most memory (some of the processes will have cryptic names, but you should be able to tell most of them).
Also, click on "System Memory" at the bottom. Look at the "Page Ins" number ... if it is large, that means that you have been running into memory issues and having to "page in and out" memory to / from disk. You can also see what your processes are using currently. I forget exactly how OSX classifies the memory in each category, but Free is memory that is totally free, and "Wired" is memory that is in use. Active is basically memory in use, and Inactive is memory that is not really being used and can be made available for other processes, but I believe its being kept around in case the process that last used it decides it wants it back.