bicycle_repair_man :
You can't have 3-way SLI as the 4690K only supports 16 PCIe lanes. You need Haswell-E.
This is incorrect. Some motherboards have a PLX chip, which is like a switch for PCI-E, this allows 3 way sli using a 16 lane CPU.
For example:
http://www.asrock.com/mb/intel/z97%20extreme9/
AMD 4-Way CrossFireX™ and NVIDIA® 4-Way SLI™ supported by PLX PEX 8747 Bridge