No. The only difference between the 1xx and 2xx series Opterons is the interconnects that allow the 2xx Opterons to communicate directly with another 2xx Opteron (in a Dual CPU setup). You won't see any difference in games or any other programs with a single 2xx Opteron vs a single 1xx Opteron.
FYI, the 8xx Opterons have interconnects that allow communication with up to 8 CPUs (4 or 8 CPU setup).