I've recently gone from 10.9, to 10.10, then back. On a 2014 15" Retina, 10.10 is slower. Slower to boot. Slower to drag/move windows (jitters). Slower login sc

I've recently gone from 10.9, to 10.10, then back. On a 2014 15" Retina, 10.10 is slower. Slower to boot. Slower to drag/move windows (jitters). Slower login screen. Mouse zoom that follows the pointer is horrible. Even with translucent off. Personally, I suspect that the Intel drivers for the Iris chipset took a crap in 10.10 compared to 10.9.