I'd like to reiterate that you should aim for a Core 2 Duo if possible. The second generation of the Core Duo procs has superior performance at the same clock speed, and somewhat better power consumption.
The 1.66GHz Core 2 Duo (or even the Core Duo) will play Civ 4 fine from a processor standpoint. The real thing you should be looking at is the video card.
If your laptop uses a video card that's 'integrated' or uses 'shared memory', it's not going to be any good at games, even Civ 4, which isn't the most demanding of games.
You want a full video card in there - it doesn't really matter what kind, but integrated graphics are the #1 performance killer.
The 1.66GHz Core 2 Duo (or even the Core Duo) will play Civ 4 fine from a processor standpoint. The real thing you should be looking at is the video card.
If your laptop uses a video card that's 'integrated' or uses 'shared memory', it's not going to be any good at games, even Civ 4, which isn't the most demanding of games.
You want a full video card in there - it doesn't really matter what kind, but integrated graphics are the #1 performance killer.