Dell E64/6500 batteries: 6 cell vs. 9 cell

Im about to order the 6400 and am not sure if I should get the 9 cell battery.

I have two questions:

1) How long does each one last?

2) Does anyone know the weight difference between the two? (and are there any major cosmetic differences)

 

John's review of the E6400 with the 6-cell battery pegged battery life at around 6:30 I think. The 9-cell would presumably have a 50% bigger battery life (just over 9 hours!), though I will not know for sure until my E6400 comes in.

 

From the manual:

I've just weighed the 6 cell at 0.317kg, so Dell's numbers are in the right range.

As for the 6 cell, a run time of 6 hours or a bit more is for a low power consumption conditions such as no wireless, nothing CPU-intensive, a dim backlight and a P series CPU. 5 hours is easily achievable. Factor in some battery wear and that could drop to 4 hours actual usage.

John