4790K comes out of the box at 4.0ghz, and is supposed to have better thermal interface material between the chip and its heat-spreader, causing it to run cooler than the 4770K. The 4690K has the same thermal upgrade and comes clocked at 3.5ghz, I believe. If you're doing video rendering with an application that will make use of hyper-threading, then get the i7.. If you are using it for games and recording game footage is what you mean, and you're going to overclock anyway, then the i5 has virtually identical performance. Either way, the xx90K should be worth getting over an xx70K.