Hello! I have a MacBook Air 13" 2015 I7/256/8GB RAM I got my Mac with 10.10 and when El Capitan was released I installed it - everything was fine and smooth as a butter... After a while I decided to do a clean install with El Capitan... So, I went into recovery mode, earased the old partition and install a "fresh" El Capitan, AND NOW EVERYTHING IS LAGGY AND SLOW. For example when you move the mouse cursor on the dock the animation are laggy and slow frame rate. When you surf the Internet and scroll it becomes slow when there are photos and stuff... I run some benchmarks like geekbench and novabench and Black Magic HD test = it all looks great! Today, I tried to reinstall El Capitan again - but it is the same! Slow and laggy. Do you suggent trying to install el capitan from a USB thumb maybe? Or maybe to install 10.10 again and upgrade instead of "clean install"? thx!!!