meaning both 6950 and 5870 had same cost nowdays and give about 400Mh/s and 370MH/s respectively, while last one - consume nearly 1/4 more power ... ~$220 each.
but if you had access to you regional distributor store, you can get 68x0's for about $100. its about 170MH/s
other way 'round.
5870 = 400 Mh/s
6950 = 370 Mh/s
yep.
until you:
1. "unlock" extra cores to turn 6950 to 6970[works on70% 6950's]
2. use phoenix miner.
3. mine w/o vectorisation w/256-worksize.
basicly 5870 is better card, except that 69x0's had Rendering back-end and more faster ram. but thats meaningful only for games/3D.
and had better power subsystem to support more hungry chip.