Like i explained to you in someone elses thread .... out of the box base and boost clocks should not be the sole factor in determing a graphics card. Aesthetics, size, cooling capabilites, overclocking potential, power ussage, price, warranty....these are all factors which should be looked at too.
I'm personally not a fan of evga cards. The evga 980's and 970's don't overclock as well as the other big brands. I don't like the way it looks and I'm not a fan of their cooling.
Also, how are you pondering and comparing gtx 970's in sli compared to an evga gtx 980 soc? base and boost clocks? You have a lot to learn..
The GTX 970sli is better performance per dollar then a gtx 980. The question you should be asking us all is, what pair of gtx 970's should you be buying