Compiling a game - cpu or gpu

[Daydreamer]

A Tim Sweeney quote from a recent Gamasutra article](Epic's Tim Sweeney lays out the case for Unreal Engine 4) might help:

For example, the team has developed new multithreading technology designed to handle up to 10 cores (UE3 couldn’t really do much with more than two). That may expand to as many as 100 if it’s necessary (it’s really hard to predict computer architecture a decade out).

I can’t say if this also applies to lighting builds, but perhaps someone official could chime in?