Using a 27" late 2012 i7 iMac, 3.4 GHz with 32gb or ram. Import AVCHD video from a wedding onto a external hard drive. Open FCPX and everything is fine for awhile, then it just starts bogging down. Color wheel spinning, everything acting very slow. Driving me nuts. Any thoughts or ideas to speed up. Am I doing something wrong here. Thanks so much, Jerry