I have a mid-2010 27" iMac with 2.8ghz Intel Core i5 processor, 16 GB of Ram, ATI Radeon HD 5750 1024 MB graphics card and a 1TB hard drive. I've noticed lately that it's been struggling with HD video rendering and I'm getting the spinning beach ball on occasion. I'm considering selling it and picking up one of the new 27" models. Is the performance difference going to be that apparent over what I have? Is it worth the upgrade? Thanks guys!