The GPU has nothing to do with such matters in After Effects.
See this page for what the GPU does for After Effects:
See this page for information about hardware for After Effects: http://adobe.ly/pRYOuk
See this page for resources about After Effects work faster: http://adobe.ly/eV2zE7
Thanks, guys! What I was trying to say was when I'm scrubbing through footage in After Effects, it lags like crazy on my mid-2010 Macbook Pro (Intel Core 2 Duo [2 cores, 2.4 GHz], Nvidia GeForce 320M 256MB, 4GB RAM). With the new computer (Intel i5 3570 [4 cores, 3.4 GHz], AMD Radeon HD 7670M 1GB GDDR5, 10GB RAM), will there be little to no lag?
Update: I transcoded my footage from my camera's codec (I use a Canon T4i) to Apple Prores 422 and things seem to be going extremely smooth.