If your game is cpu limited, the stock 4.0 clock of a I7-4790K will be an improvement over the 3.2 of the I5-4460.
Here are a couple of tests to get a better idea :
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
Limit your cpu, either by reducing the OC, or, in windows power management, limit the maximum cpu% to something like 80%.
Go to control panel/power options/change plan settings/change advanced power settings/processor power management/maximum processor state/
This will simulate what a lack of cpu power will do.
Conversely what a 20% improvement in core speed might do.