These cards, as expected, perform best @ 2560x1600:

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/avp_2560_1600.gif
In AvP, 6950 CF has 48.5% over 5970 and 71.9% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/bfbc2_2560_1600.gif
In Bad Company 2, 6950 CF has 24.8% over 5970 and 62.9% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/battleforge_2560_1600.gif
In Battleforge, 6950 CF has 10% over 5970 and 15% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/cod4_2560_1600.gif
In Call of Duty 4, 6950 CF has 3.6% over 5970 and 56.3% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/coj2_2560_1600.gif
In Call of Juarez 2, 6950 CF has 20.8% over 5970 and

**-30.7%** over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/crysis_2560_1600.gif
In Crysis, 6950 CF has 36.9% over 5970 and 77.6% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/dow2_2560_1600.gif
In Dawn of War 2, 6950 CF has 22.3% over 5970 and 75.1% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/farcry2_2560_1600.gif
In Far Cry 2, 6950 CF has 45.4% over 5970 and 36.9% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/hawx_2560_1600.gif
In HAWX, 6950 CF has 43.6% over 5970 and 33.2% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/metro_2033_2560_1600.gif
In Metro 2033, 6950 CF has 35.1% over 5970 and 32.3% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/darkathena_2560_1600.gif
In Riddick: Dark Athena, 6950 CF has 21.1% over 5970 and 51.6% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/clearsky_2560_1600.gif
In STALKER - Clear Sky, 6950 CF has 37% over 5970 and 42.3% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/supcom2_2560_1600.gif
In Supreme Commander 2, 6950 CF has 2.2% over 5970 and 9.6% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/ut3_2560_1600.gif
In Unreal Tournament 3, 6950 CF has 13.8% over 5970 and 47% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/3dmark03_2560_1600.gif
In 3DMark 03, 6950 CF has 21.8% over 5970 and 84.3% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/3dmark05_2560_1600.gif
In 3DMark 05, 6950 CF has 6.2% over 5970 and 7.7% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/3dmark06_2560_1600.gif
In 3DMark 06, 6950 CF has 5.4% over 5970 and 19.1% over 580

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/heaven_2560_1600.gif
In Unigine Heaven 2.0, 6950 CF has 96.8% over 5970 and 77.9% over 580

6950 CF is $600: that's 3.4% more then a 5970 and 20% more then a 580 but how much better then a 5970 and 580 is it? Shall we add up?

**Not counting the 3DMark benches AND Unigine bench: 6950 CF has 26.1% over 5970 and 41.5% over 580**

Not counting 3DMark benches only: 6950 CF has 38.8% over 5970 and 43.9% over 580

Counting everything: 6950 CF has 27.5% over 5970 and 42.8% over 580
That's 27.5% more power costing 3.4% more or 42.8% more power costing 20% more. To put it into perspective, 6970 costs 23.3% more then 6950 and only brings ~12% better performance then 6950.

Unless i made some mistake, i didn't arrive @ the same conclusion as W1zzard:

http://tpucdn.com/reviews/ASUS/Radeon_HD_6950_CrossFire/images/perfrel_2560.gif
Judging from this, the 6990 will totally destroy 5970 and 580: i wonder how it will stand against the dual GPU card nVidia is supposedly working on.