Sources Say Apple Originally Planned AMD Chip For MacBook Air
Several media sources (here's PC Magazine's version), all seemingly based on an account at SemiAccurate citing (but not naming) "multiple sources," report that Apple originally planned an AMD-chip based MacBook Air, rather than the Intel-based version that emerged later ("Plan B," says the report).
The AMD chips had a significantly better GPU, at the cost of a slightly slower CPU (which is a good tradeoff).
In the context of something like a MacBook Air power consumption is a far greater factor than CPU or GPU performance.