z97k is not really a thing. It appears ti be a trademark by Asus. Just get any z97.
If you want this for gaming though, the processor is not nearly as important as the graphics card. Get a 4690k instead to save $100 (Or put another $100 toward a better GPU).
For instance I use the 4670k and a GTX 980. The processor does not bottleneck at all @ 5760x1080 resolution.
The motherboard is not going to matter really about any Z97 will do the same thing it just depends on the board having what you need on it as far as addon slots and features.
For the processor the i5 4690K will give the same gaming results and their no reason to get over a 2X4 GB set of memory for a total of 8.
Just further info. This is what im looking at making. Raid Max Horus gaming case. Win 7 64bit. i7 4790 4.0 GHz. Corsair Hydro Series liquid CPU cooling with dual ARC silent 120 MM fans. 8G G skill Ripjaw X. Nvidia GeForce GTX 970 4g. ASUS Z97 K. Thermaltake 750W Smart Sp 750. 240GB Kingston SSD with a 1T HDD. LG 14x bluray drive. ASUS Xonar DGX 5.1 channel 96KHz/24bit sound card
There are a lot of complaints about that case(bad price/performance ratio). You may want to think about getting another. Other than that, just bump down the processor and use that budget for something else like SLI in the future. That will be better for gaming.
If you are thinking of SLI, you will need to get a different motherboard, Z97-K does not support sli as its second PCI-E X16 lane is a 'chipset' lane (IE 2.0 and runs on x4), which would not allow you to SLI.
If you are thinking of SLI, you will need to get a different motherboard, Z97-K does not support sli as its second PCI-E X16 lane is a 'chipset' lane (IE 2.0 and runs on x4), which would not allow you to SLI.
I was replying to Gilbadon's SLI suggestion, just in case that if the OP changes his/her mind and want to go SLI, he will need a change of Motherboard.