The nVidia 940mx is only considered a mainstream GPU. I thought all 940mx were supposed to be paired up with DDR5 RAM, not DDR3. It is probably not much more power than a 940m in that case.
It's good enough to play most current games at 1366x768 with medium graphic settings. 1600x900 is likely possible with a mix of low and medium settings. 1080p could be possible and I stress the word "could" on the lowest settings depending on the game for "acceptable" performance.
If you want a "gaming laptop" on a budget, then I recommend you drop down to a dual core i5 CPU and a more powerful GPU. For example, you will get better performance in a laptop that has a i5-6300u and GTX 960m than a laptop with an i5-6300HQ and the 940m with DDR5 RAM...