Looking for an All-in-One (iMac) for work, trying to decide between a few refurbished (by Apple) models. What affects performance more: Quad i5 Cores or Dual i7Cores. How much speed does a Fusion drive add over a regular hard drive? This one looks good but it is from 2013:Refurbished 27-inch iMac 3.2GHz quad-core Intel Core i5 Originally released September 2013 27-inch (diagonal) LED-backlit display with IPS technology; 2560-by-1440 resolution16GB memory 1TB Fusion drive NVIDIA GeForce GT 755M graphics processor with 1GB of GDDR5 memory Built-in FaceTime HD camera: or this one:Refurbished 15.4-inch MacBook Pro 2.5GHz Quad-core Intel i7 with Retina Display Originally released May 2015 15.4-inch (diagonal) Retina display; 2880-by-1800 resolution at 220 pixels per inch 16GB of 1600MHz DDR3L onboard memory 512GB PCIe-based flash storage 720p FaceTime HD Camera Intel Iris Pro Graphics and AMD Radeon R9 M370X Or do I blow the budget and get this new one? 27-inch iMac with Retina 5K display 3.2GHz Processor 1TB Storage 3.2GHz quad-core Intel Core i5 processor Turbo Boost up to 3.6GHz 8GB (two 4GB) memory, configurable up to 32GB 1TB hard drive1 AMD Radeon R9 M380 with 2GB video memory Retina 5K 5120-by-2880 P3 display. Appreciate any help.