That site is pretty accurate. I use it as a base for starting research for parts for friends.
Bottlenecks happen when one component cannot keep up with the other. In the case of CPU/GPU. Your system will be bottlenecked by the CPU only when the CPU cannot keep up with the GPU and the GPU is waiting for a frame. In most cases, this happens because either the CPU is clocked too slow or cannot provide enough PCI-e lanes to the GPU to use all that power. The 4770k has 16 PCIe lanes to give, that is enough to push 2 GTX 980 in SLI.
The 4770k is one of the fastest CPUs on the planet and has held world records for speed for a long time (7.2Ghz, granted with dry ice cooling), plus the hyperthreading, it will keep up with a GTX 980 just fine.