Guild Wars 2

I want to buy a new pc with a Intel Core i7 4820K 3,70 GHz a gtx 780 ti 3 gb 8gb RAm kingston hyperx 1600 mhz
Will this be enough ?

This setup should be enough to get you 100+ fps on Ultra (In most areas at least).

Note that if you are wanting 60fps in Zergs, I don’t think those specs exist.

There is no real reason for an i7 as an equivalent i5 will perform only a few percentage points lower (and save you hundreds of $). This is true for most 3D games (as the calculations an i7 is better at are handled by the GPU in 3D games).

I know that a i5 would be enough but i don’t play only GW2.Also i would like to know a 500W AC be enough or more?

That’s really a question to be answered by what other components you are looking to add. Most notably, the Graphics card(s) and any mechanical HDs.

Unless you are planning on running a DB server or doing some major graphics work (AutoCad, Solidworks, Creative Suite, etc.), an i7 is not needed. Again, this is true for every 3D game I can think of.