Alienware M14X R2 Very Low FPS

Hey fellas , i recently bought a M14X R2 brand bew and ever since i got it iv had problems , when i bought it it had white dots all over the screen while i was playing games but only on games so i got the Graphics card *GT 650M* but i could play games at a good frame rate and good quality but since its been replaced every single game has a frame rate of 10-15fps on the lowest graphics and on lowest resolution , i have updated my drivers and bios but it hasnt helped at all. Any help towards this would be much appreciated!