Hello everyone! I know there are existing articles on the internet about adding RAM to your Imac but i'm not feeling 100% sure yet to buy the specific RAM for my Imac so i thought i'd ask this in here with a specific question. I have a 21,5 Imac from mid 2010 with 4GB RAM. So i checked the Memory specifications Apple website and i searched on the net for Memory to add so it matches with the right speed etc. So my specific question is, can i add an extra 8GB Ram ( 4gb+4gb from whatever Brand) to my existing 4GB which is 2+2gb in each slot? So my slots look like this: 2gb 2gb (brand from apple) 4gb 4gb (other brand) 1. Is it possible to add another brand in there? Or do i have to take out the standard apple Ram out? 2. Do i need to match sizes of Ram so all 4 slots have the same size of Ram? Or is it important to have the same size in each 2 slots only? If this is all correct, would it be possible to buy and add this exact memory in my 2 slots? http://www.mycom.nl/componenten/geheugen/7138/corsair-sodimm-ddr3-1333-8gb-2x4gb#specificaties And is the 1.5V correct and it's also saying Type module: Notebook? (sorry it's in Dutch, because i live in The Netherlands) Sorry for my long post/question but i really want to sure i'm not creating any problems. Thanks in advance!!