Buying a gaming PC, would this work for max graffics on crysis 3

I'd have to agree that for most, the i7 is unwarranted and wasted power. An i5 will perform almost identically in almost all games today. Most games are optimized to only use 4 cores, aka 4 threads, which the i5 has. The i7 has 4 physical cores, but it has two threads to each core, allowing it to effectively have 8 cores. The difference in games will only flesh out if you have a crap ton of other heavy programs running at the same time (i.e. video rendering software, etc.) or when games finally start using more than 4 threads/cores (this is already slowly starting to happen with the latest titles).

You may think then, that it's a good idea to buy an i7 to future-proof and get better performance when your hardware starts to fall behind the times and 8+ threaded games become the norm. Possibly, but most current games don't push harder at all than most CPUs (like the i5) can handle, so it's a trivial argument. And keep in mind that since you're future-proofing is also built around hardware from today that supports the CPU (most importantly, the motherboard), you may find yourself missing out on new things like more PCIe lanes, new peripheral port specifications, RAM speeds and standards, that sort of thing. And it'll all be available for cheaper in the future.

On top of that, I'd say that the best target to future-proof the heck out of if you're going to try to is the GPU. A rule of thumb is to spend (at least) 1.5-2X more on the GPU than the CPU in your system. Emphasize a single, strong card before stacking on a second, third, or even fourth card. What some people do is they buy the first one, and when it starts to age, they get a second identical one a few years down the line when they can be found for cheap even when new.

So what does this long, winded explanation say? If you have the money, get an i7 if you so desire, but if money is tight, it's better to look long and hard at an i5 setup with a better GPU. With an i5, I'd recommend a single R9 280X, a R9 290 or a GTX 970 at least. Personally, I went with 2 R9 280's in Crossfire (but they were very cheap for the performance at $175 each during Black Friday). You can get a 280 for about $200 right now, and they are only slightly behind the GTX 770 in benchmarks for significantly less. That's another viable option. People with money to burn commonly buy the i7 and two R9 290 or 290X's, GTX 970's or 980's. Get the overclockable K-version of either processor if you're sticking with a Z97 motherboard.