The issue is your CPU. As Sonic himself would say, "You're too slow." More seriously, Sonic Adventure 2 is not demanding on the GPU. In Dolphin, the GPU determines how high you can raise things like your resolution and anti-aliasing before those settings cause bottlenecks and slowdowns in emulation. The rest is largely up to your CPU. That is to say, if your GPU is sufficient for your current graphical settings (which it is in this case) the problem is your CPU then.
Make sure your CPU is turbo-boosting correctly. If you're running at 2.4GHz, that's going to cause slowdowns (even though SA2 is a fairly average game in terms of CPU requirements). Google for "dolphin emulator laptop performance guide" and look at the part specifically about CPU Performance.
Make sure your CPU is turbo-boosting correctly. If you're running at 2.4GHz, that's going to cause slowdowns (even though SA2 is a fairly average game in terms of CPU requirements). Google for "dolphin emulator laptop performance guide" and look at the part specifically about CPU Performance.