I have a MP 5,1 with stock 3.33ghz 6-core W3680, 6gb ram, and an Sandisk SATA SSD. Still running Snow Leopard (!) so will be upgrading to El Cap soon. I'm trying to figure out which upgrades would make an actual difference in daily usage (used for Parallels Virtual Machine, Quark and InDesign, light Photoshop and Illustrator). Photoshop and Illustrator use is frequent, but nothing too heavy--designing book and magazine covers. We're getting a bunch of new 27-inch iMacs, but I want to keep this one computer running too! Here are my plans, in order of priority: Definite: 1) Upgrade ram from 2x2x2 to 8x8 (paired DIMMs are still ideal, right?) 2) New video card 3) 4K monitor (probably Asus PB279 -- have one on a Mac Pro 1,1 that works great) Possible: 4) Upgrade from SATA SSD to PCIe SSD 5) Upgrade W3680 to ?? Would upgrading the W3680 to a single processor X5680 make a difference? I kind of doubt that dual processor would matter too much, but I would consider it. All MP 5,1s support dual proc right? Any thoughts appreciated!