not sure, if they sell an i5 model that is identical with the only difference being that it has an i5 instead of an i3 (and other stuff too maybe like more RAM or bigger HDD but that stuff is irrelevant) then you could try to find the exact i5 that is in the i5 version online or locally somewhere and then install it yourself. But usually, it's not possible or not recommended. That's the price you pay with a laptop, you get portability but you lose out on customization and upgradeability