The 2012 iMacs are about to be released. Before you place your order, it’s important to know the memory options for each model. The memory is not user accessible on the 21.5″ model. This means that you’ll need to pick an 8 or 16 GB model when you order it. Once you own it, you can’t upgrade it – so, like Indiana Jones, choose wisely. The 27″ model will be available in 8, 16, and 32 GB configurations. This model has 4 memory slots, which are user accessible.