Now it sometimes restarts its elf even when im not using it, very annoying! It has only done this since I put the new RAM in. But then all of a sudden about 5 mins into surfing the web the screen went blank and it started to restart itself. I have just upgraded my mid 2012 MacBook Pro to 16gb using 2x 8gb ATech DDR3 12800 1600MHz and to start with everything was fine, booted up quickly etc.
