Newegg has an HD 7870 for $170, it is rate as mining at 375 khash. The 7950 is pretty much the same as 7970 for mining and cost $430 giving roughly 700 khash. Thus 2.2 khash per $ vs 1.6 khash per $.

      I am considering buying 2 7870s for $340 and using them in my computer in sli mobo which works fine for mining. However most people are buying 7950s and r9 280x and 290x which is what has jacked up the price, this the reason I'm considering an option almost 100 cheaper giving 50 more in khash.
   What do you recommend?