Turbo speed can be automatic or manual depending on the motherboard and drivers.

Monsen is completely right. CC doesn't use any of the fancy differences between the two. I'd like to point out that the 7600 is 0.2GHz faster. The clock speed is probably the only difference between the two relating to CC3+. That probably won't be a noticeable difference. The 7600 might be faster by 4.4% at most. It's almost backward: the cheaper processor would run CC3+ better.

Here's an update. I added some detail. I'm stepping back to evaluate the entire map.

Click here for the larger gallery image.

All, much better. Thank you!

You could try a darker color. At least that would differentiate the rivers from the sea. Rivers to me have always been darker than other bodies of water. I think it would have the effect you're looking for.