i5-6200U is a dual core with hyperthreading (2c/4t), i7-6700HQ is a quad core with hyperthreading (4c/8t), and yes, there is a pretty big difference in performance, the i7 will slaughter that i5; as the "U" is part of the "ultra low power" cpu lineup, and won't come close to the turbo clock speeds of the i7 (to say nothing for the core and cache advantage of the i7).