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No. For the same usage, divide battery life by about 2, you'll get a good estimate that way.

Since windows isn't as "machine specific" as OS X, it has not been optimized to do proper power management on this specific computer, hence there is no way it'll ever be able to achieve as good a battery life. It's all in the software. Mac OS X does a lot of stuff under the hood to keep battery life up.
 
Ever since I started using it in the tiger beta, it's been terrible, no mater if it's XP, Vista, or 7.
Best I've ever seen is about 4 hours.
2.5 is about average for how I use 7.
 
It also can't use the integrated so it is always running the nvidia card tearing the battery up.
 
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