Recently my 2012 MBP 15" has been taking an abnormaly long time to boot especially considering I replace the HDD with a Samsung 840 Pro. So I decided to run the Apple Hardware Test and it just stays on the first step (checking the memory for nearly an hour) I already restarted it once. I have 16GB of RAM. Would it have anything to do with the issue? Thanks
Perhaps something is wrong and causing this slowdown. Maybe a visit to your local authorized apple dealer may be required. They'll be able to tell you what's wrong and fix it if need be.