Any water cooling temps ultimately depend on the radiator and the fans. Bigger radiator is more cooling, and there are very few exceptions to that. Is it worth the money? It depends on how cool you want to keep your CPU. H100i v2 will probably keep your CPU under 60C even under the heaviest loads, and leaves quite a bit of room for moderate overclocking as well. If you're going to be doing higher end overclocking you may want the 115i.