Thank god for zombie threads! This problem has been plaguing my Vaio Svs15 for years now. CPU 0 has been pegged at 100% since I bought the **** thing, and you guys have finally (finally!) put me onto the solution. I knew it probably had to do with the SSD I added, but I had no idea about the "3rd pin" possibility with the caddy. I popped it out after reading this thread, and interestingly there is clearly a cut-out in the casing for a switch, but it's empty. I've got a new one on order for $9 that purportedly has a switch. I'm so excited, it's almost like I'll be getting a new computer in a couple days.