Which laptop is best for league ?

Buying a new laptop and need to know what I should buy... As of now I think I am able to get a discount on HP laptops through my internship, so im going with HP for cost reasons. I am heading to school in the Fall and want something that will be good for schoolwork, but I also want to be able to play some games (mainly league). I've been looking at the HP Envy 15t. The stock version of this laptop comes with 4th Gen Intel(R) Core(TM) i7-4720HQ Quad Core Processor + Intel(R) HD Graphics 4600. Wanting to run games close to high or on high settings (mainly league) I was wondering if it was worth 140$ to upgrade to 5th Gen Intel(R) Core(TM) i7-5500U Dual Core Processor + NVIDIA GeForce GTX 850M 4GB Discrete Graphics instead of the stock processor. With the 140$ upgrade im looking at 750$ or so without discount. Is this worthwhile or should I keep looking?