Difference between different intel i5 models

Solution
The difference is the primary base clock speed of the chips. The faster (bigger) the clock, the faster the CPU can process data. Most users, that use their PCs for websurfing and basic office type programs, wouldn't notice much difference between the chips, you really only need higher clocks if you do higher end gaming or things like video processing. So, it comes down to what you plan to use the PC for, as well as the other components in the system (no point in putting a higher end chip in a system that is made up of otherwise inferior parts that won't keep up).
In the same architecture of core i5,for an example haswell all core i5 models except the unlocked ones who can overclocked,are the same chip with different clocks,so 4590 is like 4460 with higher clock speed.
 
IMHO the best value for money available at the moment is the build I just did (see my signature).
The other haswell i5 chips cost a bit less. They will do the same job, just a bit slower. The more you spend the faster the chip. When your PC is new, you probably wouldn't notice the difference, but as it gets older, you would see the difference more and more.
The new Skylake chips are a bit faster, but the extra expense is not worth if at the moment.
 
The difference is the primary base clock speed of the chips. The faster (bigger) the clock, the faster the CPU can process data. Most users, that use their PCs for websurfing and basic office type programs, wouldn't notice much difference between the chips, you really only need higher clocks if you do higher end gaming or things like video processing. So, it comes down to what you plan to use the PC for, as well as the other components in the system (no point in putting a higher end chip in a system that is made up of otherwise inferior parts that won't keep up).
 
Solution
It's an excellent chip, but again selecting a chip should be based on what (and how) you are planning to use the PC for. For example, if you are not overclocking, you can save some money by getting a non "K" version. If you need hyperthreading, and have a good GPU, you can opt for a Xeon, which is basically an i7 without the integrated graphics for a lower price. Things of that nature.
 
Its for gaming. There are really big games coming in the followin years, so i guess i would need a good processor like 4670.
But i got no intention on overclocking it, so 4670 it is.
How much difference it will make if i get the i7? I mean, am i gonna need really powerfull MOBO and PSU?
 



i7 have no difference in gaming,only in tasks like video rendering etc.Better invest money on gpu than core i7.