The 4790 is a 3.6 GHz Base clocked CPU capable of ramping up as needed to 4.0 GHz it has a TDP of 84W. This i7 is locked for and is not suitable for overclocking. This can be thought of as a standard version of the 4790. It offers a mid-level of performance and energy usage compared to the other 4790 CPU's compared here.
The 4790k is a 4.0 GHz Base clocked CPU capable of ramping up as needed to 4.4 GHz it has a TDP of 88W, This i7 is unlocked and is suitable for enthusiast looking to overclock their CPU. This CPU offers the best performance and least energy efficency of the three CPU's compared here.
The 4790s is more interesting for those looking to build small form factor computers and / or save on electrical cost.
This i7 is a...