Call of duty black ops 2 fps problems

[TheAmazingGeek]

Just started play black ops 2 again and i found that it was only running at 40 fps
my specs are
GPU 980 superclocked
CPU intel i7 3820 3.6 Ghz
corsair vengeance pro 16 GB DDR3
ASUS 24in 144Hz 3D Monitor

do i need to allocate more memory maybe ?
or could it be a problem with my monitor being 144Hz ?

can anyone help me ?

 

[iamlegend]

What is your Monitor Resolution?