So you probably would get No lag with it set on medium, low, 4 and 90% with a gig of RAM, and possibly no lag to very low with any higher settings with 2gb RAM.
Don't forget to check IGN's OPTIMIZATION GUIDE for the best settings.
If you played the sniper that doesn't mean you have to pick the snipers unlockable weapon. Players with higher rank will have a higher priority when they apply for Commander position.
The same principal works with squads and you'll be the squad leader if your leader leaves.
That's Catalyst / Drivers 5.6 for ATI owners, and Nvidia 77.50 Drivers for you Ge Force owners.