Ok, so I pulled the trigger on a 256GB Samsung 840 PRO SSD a few days back and replaced my 15" Mid 2012 cMPB's 750GB HDD (7200 rpm) yesterday. Eventually I'm planning to have the ssd in a caddy (still waiting for it to ship) replacing the superdrive and have the hdd in it's original position, but as the OS is going to run on the ssd and I wanted to install from scratch I just switched them out for the time being. Let me first say, it's like having a brand new computer, I'm really impressed with the speeds. Photoshop opens up as fast as TextEdit did before the switch. Everything is super fast and snappy, however, I can't say the same about boot times, they seem to vary anywhere from 0:45 to 1:15 minutes to the login screen (before I got about 1 minute). I reset the pram/nvram, fixed all permissions and set the ssd as the startup disk, which seem to be the most common recommendations to slow ssd bootup times, to no avail as I still keep getting the same times. What confuses me especially is how inconsistent the times are. I don't think it has to do with the selection of the startup disk either, as the apple logo shows up fairly quickly. The timeline looks something like this: 0:00 Press Power Button 0:05-0:08 Apple Logo Appears 0:10-0:15 Spinning Wheel Appears below Apple Logo 0:45-1:15 Login Screen Appears so, as you can see, the largest part of time is spent on the spinning wheel part (I counted 20 spins last time, I have read others have as little as 3-4 spins). I don't think the ssd is faulty, as everything else is extremly fast, I also measured the speeds and I'm getting about 480 write and 500 read (TRIM enabled). Has anyone ever encountered similar problems? What else could cause this? Any help is greatly appreciated.