Hello, I am a very happy owner of a 2009 20" iMac that has been running great with Snow Leopard since I bought it. I always was tempted with each OSX release, but ended up never upgrading. Thing is this time I am really tempted hearing how great El Capitan is and after experiencing the OS on my retina macbook pro. But the thing is I dont want my iMac to be seriously affected performance wise. I do understand that performance will take a toll, but I am not sure if it is tolerable or it just ends up making me cringe everytime I use it. So, without further ado, are there any similar iMac owners that have tried upgrading to El Capitan? Would prefer to hear from people with stock HDDs and not SSDs. I have upgraded my memory to 8GB but I am interested how the machine performs with HDD. Appreciate the feedback.