Intel Core i7 4770K  vs 4770 

Intel Core i7 4770k and Core i7 4770 are almost identical. The only difference is that Core i7 4770k has an unlocked multiplier to achieve higher clock speed during overclocking while the Core i7 4770 is a simple processor with locked multiplier and only supports Turbo Clocking that is also up to a certain limit.

If you are building your system from scratch and only want to play latest games, use Adobe Photoshop for casual photo editing, watch movies and burn DVDs then buy the i7 4770. There is no need to for an unlocked processor. You don't even need to buy a separate mid ranged graphics card since the on board Intel HD 4600 Graphics on i7 4770 is powerful enough to run games like FIFA, Call Of Duty on normal settings.

But if you work in multimedia industry where you need to render 3D images and 1080p videos, then Core i7 4770k is the right choice for you. Since the rendering process is heavy and requires more processing speed, you can overclock your i7 4770k to gain the extra bump in speed while rendering.

Now, in a situation where you already have a Sandy Bridge Core i5/i7 or any Ivy Bridge processor, there is no need to spend those extra bucks on upgrading your processor. Instead, you can spend these extra money on upgrading your graphics card or increasing RAM.