The 4820k is a bit cheaper and a better perfomance above the 4790k
http://www.futuremark.com/hardware/cpu?_ga=1.47457572.2021832007.1402944213
if it is the 4790k I will use it with a z97 mobo and msi gtx 770
if its the 4820k i will only change mobo
http://www.futuremark.com/hardware/cpu?_ga=1.47457572.2021832007.1402944213
if it is the 4790k I will use it with a z97 mobo and msi gtx 770
if its the 4820k i will only change mobo