Be aware that many times manufacturers list optimistically high battery life with actual battery life being lower; sometime listed battery life is as much as 2x longer than actual battery life.
Actual battery life depends on actual usage. Usually when professional reviews are written about battery life it is based on "average" daily usage which excludes playing games and anything that stresses the CPU or GPU for a long time like video encoding or image processing.
Going into your system settings and select Power & sleep. Then, click on Additional power settings. If your set for the High performance power plan, your battery will get drained a lot faster. Set the power plan to balanced to improve battery life.