M15x and battery problem

Hello everyone , this is my first post! I follow you from a lot and I found many useful tips .
I live in Italy but this is not a forum we dedicated so interesting .
I come to the point : I have an M15x un bought used recently . it's Fantastic!!!
I purchased separately battery original parts 9 cells but the lifespan is only 3 hours with brightness at minimum and not using the laptop but leaving it switched on .
It's the second battery, the first battery it's one compatible parts and its duration only 1hour but it's only 6cell.
Now I do not know what to do . What can the duration it's so short ?
I done a fully charge/discharge and the discharge power with alienhead but my laptop don't improves.
I apologize for my English not very fair .
I am studying.
Please help me!!!

thanks guys

My configuration m15x

intel core i7 q720
8gb ram ddr3
250 gb ssd pm800
gtx260m 1gb ddr3
15" display
windows 7 - 64bit

 

That's the usual lifespan of the battery on that platform. The machine requires a lot of power to run. Our recommendation has always been to game with the machine plugged to the power outlet.

 

Thanks for the answer! Also not playing but only using Photoshop or web research battery life is.
I apologize for having opened a threat to no avail!