VRAM doesn't directly impact the raw performance of the card, it is useful only when you need it, GTX1060 3GB is still a better pick than GTX1050Ti 4GB Strix version if you want more performance out of the box (as in higher frame rate) 

Switching from i5 to i7 doesn't benefit you at all if the games you play don't need that extra horsepower of i7, and you need to top up RM 500+ if you upgrade from i5 to i7, you better spend the money in a better GPU instead, at least it provides a better price/performance ratio in overall.

For example:
1. i5 + GTX1060 = 60 FPS in games
2. i7 + GTX1050Ti = 40 FPS in games

First option is clearly a better choice here.