so I'm going to be getting my late 2015 iMac 5K soon. It's coming with a 2TB fusion drive and only 8GB of RAM. What type of RAM should I expect to be receiving....2-4GB sticks, 1 8GB stick? I want to end up with 32 GB or whatever I can max out. I think that there are 4 slots onan iMac. Also, I'm going to give the 2TB fusion drive a chance before I think about upgrading to an SSD. Thoughts?