It does make a difference... but because the GTX950M is a mid-level card, you'll probably find that as soon as you get anywhere close to your game using 4GB graphics memory, the GTX950M won't be able to cope with it. 2GB is probably fine.
But yeah, my "official" recommendation would be the Dell I posted:
- Within budget
- This particular i5 is better than the i7 in the ASUS I posted
- GTX960M is better than the GTX950M (and has 4GB virtual memory...)
- 256GB SSD
- 8GB RAM