I watched Activity Monitor while doing some tasks, web browsing, playing a video, opening large image files and the like.
4 GB - Showed too many Page Outs and Swapping for my liking. When I threw in some intense file copying between drives on the Firewire and USB ports the Page Outs and Swapping were unacceptable.
8 GB - Saw no Page Outs of Swapping with the above tasks, however when I started moving large files between multiple drives along with 'routine' activities the Page Outs and Swapping started to show up.
IMHO - 8 Gigs would be fine for most people, and I thought it might be fine for me but am now rethinking that.
I have some more testing to do tomorrow and and gonna really throw some stuff at the system before I decide on how much RAM I will find acceptable over the long run.
For the 2011 iMac I found the following RAM Prices from OWC.
16 GB ( 4 X 4GB ) $91.99
You could also buy 8 GB module but the price more than doubles.
16 GB ( 2 X 8GB ) $247.99
For me I might opt for the more expensive option, because if I bought the
16 GB ( 4 X 4GB ) $91.99 option and found out 16GB is not to my liking I'd be stuck.
Buying the
16 GB ( 2 X 8GB ) $247.99 will give me the 16 GB and leave open two slots just in case I decide to add more later on.
Here is where we order memory from ................
http://eshop.macsales.com/shop/apple/memory/
FWIW: We have ordered quite a few things from them and are very happy.
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