I have inherited a mid 2011 iMac 21.5inch, 500gb HD, 2.5ghz intel core i5 with 4gb memory. Ive been using MacBooks and iPads for a few years and have essentially only taken this because Im having to work from home for the foreseeable as Im sure many of us are. Thing is i REALLY like it! Ok, its pretty dated but it actually still does most of what I would ever want a desktop to do albeit its a little slow. Running along side this I am just finishing a house renovation where I will have a dedicated office space that at some point I would maybe consider putting a new iMac into, but spending that sort of cash isn't a top priority right now. So here is my question. What could I do to the iMac that would make any significant performance differences and how much would it cost? Obvious thing is the memory, how much would that cost me? (link if possible). I don't want to spend money thats just dead but if I can make it a bit better then I will because as I say its doing 99% of what I want it to already just a bit slow. Maybe its not viable to do anything, if so, fair enough. These machines really do have a remarkable shelf life.