What's the highest AA in Crysis??

I just installed crysis but I can only choose up to x8 in AA. My friends who also have the game can choose up to x16 in AA and even x16 Q, whatever that means. It's not like the option x16 is there but I can't select it, it doesn't EXIST! I only have up to x8 in my AA meny and no other options exist. I have a much better computer than my friend. I have the Radeon 4870X2 graphic card, quad core cpu at 2.4 MHz and 4 GB RAM.
I can run Crysis in Very High at 1680 x 1050 with x8 AA without any problems! So what's the issue? Is there some problem with my installation? Didn't those options get installed? Do anyone else have the same problem??

Thanks in advance!