Issue with 7950 on The Amazing Spiderman

Hi, I have an issue with The Amazing Spiderman. I have a 7950 boost, and I'm having lag spikes, my fps is droping to 30-40 fps sometimes. I tried to search on this and there maybe an issue when using a radeon card with The amazing spiderman. Some says they are using 550 Ti and they don't experience any lag. While those who use 7950 (obviously a better card) encounter lag. I was hoping someone has an idea on this. Thanks!