Almost all games use only one to four cores, so those extra cores (which aren't full cores anyway, a lot of components are shared between two cores) will sit idle. And since core for core Intel's cores are much faster you'll end up with better performance with the i5.
This is also why I'd recommend the 8350 if you're building a workstation. In that case you'll actually use all 8 cores, making it faster than the 4460.