for gaming gpu is king, cpu does help but is secondary.
Also on that scan model you can customise it, so you can add extra storage and upgrade the cpu to an i7 if you want the hyperthreading.
I5 chips per core performance is very similar to i7, they are almost the same, i7 just offers hyperthreading on top which in a highly threaded game as a best case scenarion can maybe give you an extra 30% or so cpu horsepower. But the cost difference betweem i5 and i7 is way more than 30%.
The gpu is not worse its the reason I recommended it. A desktop superclocked 970 with 4gig of vram is not worse than a mobile 8xx chip with 2 gig of vram.