Macbook Pro 13 inch vs 15 inch for Gaming

15 inch has discrete graphics for high performance situations. I would get that one.

If you get the 13inch all settings will have to be at the lowest setting possible which makes gaming possible, but if you want a better experience you will need to get the 15inch with discrete graphics.

try getting a 13inch with higher graphics RAM and it should be fine and since you are gonna get a bigger monitor in future its logical to go for 13" only

This is not true, the bigger monitir will not change the fact that you are using a limited integrated graphics. If anything getting a bigger monitor and using the integrated graphics for gaming on the monitor will make your experience even worse because the gpu will have to push out more pixels than on the 13inch screen requiring more rendering and less fps.

hmmm but wont a better processor and gpu ram not suffice to certain extent?...(genuine doubt i dont have much tech background)

First, MBPs are poor gaming machines. If that is your top priority, get a PC.

If you must choose between the 13" and the 15" MBP, CT has it right, get the 15". The performance will be much better.

Ciao.

If you have to get a 13inch then you will need at least 8gb of ram which will increase the vram to 512mb and as I said this will make gaming for certain games possible, but settings will have to be at low. For example I have an early 2011 13inch and played diablo 3 at highest resolution, no shadows, and everything else at low and I had fps between 25-30. This made gaming possible, but not the greatest experience because things were blurry and it made the graphics look outdated. I now have a 15inch retina which has the discrete graphics and I can play diablo 3 at an even higher resolution than the 13inch with medium smooth shadows and all other settings at high and it runs at a consistent 30fps.

Keep in mind the 15inch retina has a discrete card with 1GB of vram and the lowest model 15inch cMBP has a 512mb vram discrete card, but if you go to a higher model then you can get 1GB of vram.