The fact that you install your OS on WD10EARS-00Y5B1 is the problem. These drives are slow, only 5400rpm, benchmark shows that they are much slower than WD BLUE one even they have double cache size, and even slower than Seagate low power 5900 rpm. Many of my friends ask the same question as you do and some how i feel kinda stupid. Please use the product as recommended, don't install your OS on a GREEN drive. Install it on a normal 7200rpm drive and your problem will be gone.