AMD radeon 6770 issues

Hi all, I have an MacBook Pro 15 inch with AMD radeon HD 6770M running Mac OS X Lion.

I have a problem with performance and i just noted it in dock, because dock animation is running with a little lag.

I used glxgears to test frame rate of my mac and I get 300 frames in 5 seconds every time.

I think this is a problem in Lion, because one friend of mine have the same MacBook with Snow Leopard and the video performance is amazing.

In Snow Leopard the same MacBook made 15000 frames!

Anyone can help me ?

Thanks a lot.