It's simple. It's all about the CPU. I don't think you'd have an easy time trying running it smoothly on a laptop, especially a mac.
Also, sandy bridges are better since they have some technology that's supposed to make Dolphin run better, here's a list of cpus that should be better for dolphin (scroll to the mobile section):
http://en.wikipedia.org/wiki/Sandy_bridge
My quad-core 3.2 GHz (not an intel unfortunately, it's a phenom II) with a 560 Ti makes skyward sword playable, but I must say it's annoying when in larger areas it drops below 25fps. No way a 2.2 Ghz could make it playable imvho.
About the video posted: gamecube titles will run fine I guess, and mario kart wii is pretty light on the graphics side. I bet he can't run skyward sword nor any other more complex wii title though.
So yeah, the second configuration could be worth it if you're interested in gamecube titles and if it's not that much more expansive. Other than that, don't expect complex wii games to run great.
What game are you having trouble with? I use HLE and have no problems with Skyward Sword, Mario Kart and Resident Evil (the only games I played so far on Dolphin).
I solved my music stuttering issues in Skyward Sword by setting XAudio2 as Audio Backend, by the way.