Intel I5-4670K or 2nd 660 OC’d for my current system? please help!

Currently I have an AMD FX 6300 6 core overclocked to 4.10 GHz and a gigabyte 660 OC edition. I’m looking to upgrade something, should I go with another 660 in SLI ( I heard its equivalent to a 680) or get the Intel I5-4670K and new motherboard? I use my computer strictly for gaming, recording my gameplay, and uploading it to youtube… and of course just searching the web.