Battlefield 3 lag

[Yoto]

Just got Battlefield 3. When I first started to play I would usually get 40 to 50 fps (not in combat) but when I do get into combat my fps drops to 30-23. My computer specs are:
AMD Phenom(Tm) X2 521 Processor 3.50ghz
4 Gb Ram
Nvidia Geforce 550 ti 1gb
600w psu
I have watched videos on youtube with the graphics card I have and usually the person would have 40-70fps. I tried lowering my resolution and also graphics but I still get the same results.

 

[coolbir]

there might be a problem with your graphic card get it checked