Hi!

I recently bought a Dell Inspirion 15 7000 Gaming Series (7559), basically this one (with minor differences, mine has 4gb of video and a hybrid hdd):
http://www.pcmag.com/article2/0,2817,2497197,00.asp?tab=Specs

But in here in Brazil Dell offers it with a custom Ubuntu 14.04.1 (with a custom kernel, because of the skylake processors).

This laptop comes with:
Processor Name: Intel Core i5-6300HQ 2.3 GHz (base)
8 GB LDDR3
Nvidia GeForce GTX 960M 4gb DDR5 (running on 364.19 drivers)
1 TB HD (8gb ssd cache)
Resolution: 1920 x 1080

Everything works well with Ubuntu, but I'm having weird performance with games:
Some games run super well, Distance for example runs at 60 fps with everything on max. Divinity, Xcom 1, Dirt Showdown runs well too.
But other games run poorly, like Xcom2 (av. 17 - 25 on min and some effects), Borderlands 2 (av. 15 - 25 on min-med) and Shadow of Mordor (av. 20 - 32 on min-med) runs poorly.

Xcom2 I kinda expected, for reasons already know, but Borderlands2???!

And the funny thing is this:
Borderlands 2 starter without lighting and shadows (I had to edit a config file to activate it) and changing the resolution and lowering the configurations doesn't help much.
Before editing the config file I had 35 - 40 fps with "everything on max".

Soo... anyone with the same experience using nvidia mobile GPUs??
I have tried all the "common" things, like playing with different configs and putting "__GL_THREADED_OPTIMIZATIONS=1 %command%".

Any help or tip would be great!

Thanks!