*UPDATE* Windows 10 fixes the problem completely for some reason ..i am 90% sure. (Not 100% because i haven't tested it myself as i still have windows 8.1) I have asked like 3 people with exactly the same graphics card that used to have the same problem in win 7 and 8...and upgraded to 10 and the terrain bug disapeared completely! When i upgrade to 10 i will let you guys know here.