Hi! I currently have the Surface Pro 2 i5 4300U with 256gb hard disk and 8gb ram. I am pretty okay with using the Surface Pro 2 but only one thing. Need a bigger screen and a lighter tablet. So I am considering the Surface Pro 4. I am confused between the i5 model with 256gb hard disk and 8gb ram or the i7 model with the 256gb hard disk and 8gb ram. My question is if it is worth spending more for the i7 model? I read that the i7 model has the iris display card which is better than the one in the i5 model. Is it really worth it or will the battery drain faster with the i7 model?