My bad....must be tired at after midnite ....took the 9 for an 8
http://www.techpowerup.com/reviews/ASUS/EAH5970/31.html
That makes the decision much easier given the huge heat, power, noise differences and the 670 still has a 13% speed advantage. I used two aftermarket Asus cards as couldn't find reviews on reference versions for both.
That above ling says that the fancy Asus 5970 gets a 100% to the 5870's 68%
The previous link says that the Asus 670 gets 100% to the 5870's 55%
-Performance wise, the Asus 670 has about a 13% advantage over the Asus 5970
-Power wise, the Asus 670 pulls a about 52% (158 watts) of the power and produces about 52% of the heat of the Asus 5970 (304 watts)
-Noise wise, under load, the Asus 670 (25 dbA) is about 1/6th as loud as the Asus 5970 (49.1 dbA)