You should be able to play most games at medium graphic settings and some games with high settings to get good performance. The exception would be games that are graphics demanding like Far Cry 3 and Metro 2033. Those games are best played at medium graphics to get decent performance.
The GT 635m a decent step up from my GT 550m which is provides pretty good performance. Of course compared to other nVidia GT 6xx cards the GT 635m may only seem okay.
Anywaste, if you have a low budget, then there is nothing you can really do about it.
but what do you think about laptop with i3 and geforce 630? do you think it would be much worse?