Memory purchase question
I have a late 2009 i7 2.8 quad core iMac. I do video editing with iMovie and ScreenFlow. Right now I have the standard 4GB Apple memory in it. I am thinking of upgrading would 8Gb total be enough or should I go higher? Also does the memory have to be installed in pairs? Almost forgot do all the modules need to be the same brand? Thanks for the help.