Each step up gets more cache size, turbo boost, hyperthreading, internal graphics, cpu features, and power options, depending. Also, i3/i5/i7 isn't the only thi

Each step up gets more cache size, turbo boost, hyperthreading, internal graphics, cpu features, and power options, depending. Also, i3/i5/i7 isn't the only thing to consider - look at the product suffix (U/Y/T/Q/H/K) that adds or removes features to that model. Compare the i3-6100U to the i7-6500U - both skylake ultra-low-power CPUs [1]. The i7 has about 30% faster effective clock speed (plus the turbo boost, which gives a small jump in clock speed when necessary, which can reduce battery usage) and 25% more cache. But another i7 model, the i7-6550U, has better graphics, even faster turbo boost, and a bunch of "Pro" Intel features that neither of the others have. Move up to the i7-6700HQ and now you have two additional cores, incredibly faster performance, even more cache, and higher limits up the wazoo. Of course, newer microarchitectures may have have more optimal code paths, slightly higher clocks, smaller dies, better graphics, and use less power. So an i5-7200U may have better performance, similar features, and use less power than an i7-6500U [2]. [1] http://cpu.userbenchmark.com/Compare/Intel-Core-i3-6100U-vs-Intel-Core-i7-6500U/m37381vsm36930 http://cpu.userbenchmark.com/Compare/Intel-Core-i3-6100U-vs-... [2] http://cpu.userbenchmark.com/Compare/Intel-Core-i5-7200U-vs-Intel-Core-i7-6500U/m153577vsm36930 http://cpu.userbenchmark.com/Compare/Intel-Core-i5-7200U-vs-...