I'm a graphic designer and no gamer. I want the new iMac 5K and use it for Photoshop, Illustrator and InDesign work. If I dont go fully upgrade, which part are more important to upgrade: 4Ghz CPU or 4GB M395X? or can i saddle with 2GB M395? I will choice 512GB SSD and upgrade the memory by myself. Today I use my haswell rMBP 2.6GHZ, 16GB ram, 512GB SSD and Iris Pro.