Maximum ram?

I have a early 2009 20 2.66 imac.

Officially it max's out at 8gb. But would it be possible to install x1 (8gb DDR3 PC3 8500s 1066Mhz SODIMM) from late 2009 imac along with x1 4gb stick to make 12gb in total? The ram spec for the late 2009 model seems to be the same – is this correct, and would it make any difference?

 

I believe the maximum is 8GB in total (2X4GB). http://www.everymac.com/systems/by_capability/actual-maximum-ram-capacity-of-macs.html

 

Cannot, 8G is the max for iMac 9,1 at this moment. Of course, if you can get a full refund from the seller, there is nothing wrong to a 8G stick and test it by yourself.