Also have you opened up the case to verify what ram sticks are in there? Google does show it having 12 gb or ram but as others have said I don't think a 12 gig stick exists, it very well may be what post 2 stated

Yeah its a 8and 4 i can see 2 stick

Yeah then that's an easy fix, just get one the matched the speed of the 8 in there already and replace the 4 as post 2 said and you should bee a big increase in performance, hopefully