DELL alienware m15 battery 60W vs 90W, which one is better?

                                            dell alienware m15 review video
On www.dell.com, this is how they describe this battery: "In addition to extraordinary power and portability, the m15 offers incredible battery life, with a 60WHr battery and an optional 90WHr upgrade, that can keep you on the move with up to a 17-hour life span on idle*." Luckily we have both batteries in stock, you may check them as below, we listed the battery detail and link, hope it would help you out.

Brand new dell alienware m15 2018 15.2V 3750mAh laptop batteries

Voltage: 15.2V
Capacity: 3750mAh (60Wh)
Battery cells: 4-cell
Chemical: Li-ion
Battery Color: black
Condition: new original battery
Warranty: 9 months

dell alienware m15 11.4V 7890mAh laptop batteries

Voltage: 11.4V

Capacity: 7890mAh (90Wh)
Battery cells: 6-cell
Chemical: Li-ion
Battery Color: black
Condition: new original battery
Warranty: 9 months