Answer to: MacBook Pro lags considerably doing simple tasks (i.e. loading apps)I have a Mid 2010 that started doing that and then it would not boot all of a sudden. It just sat at the boot screen. I put in another drive same thing. I bought the HD SATA Cable and it works great now. Do not buy it from iFix it. Prices are way too high. Go to ebay. Infact I have replaced my whole LCD Display and the plastic cover on top of the display. Works like new and I saved a bunch on ebay. Unless you have money to throw away.