I've seen you post this type of thing in a number of threads, it just doens't make sense.
If the dual core and single core cost the same amount, why on Earth would I not compare them if I'm looking to buy? If this Fermi costs as much as a 5970, I don't see why I wouldn't compare the two.
Who makes up these rules on what is a 'fair' comparrison? Is it fair to compare a GTX480 to a 5870 when the 5870 uses only ~60% as much silicon and nearly a billion less xtors? Is it fair to compare a 5870 to a GTX480 when the GTX480 has 50% more memory? Is it fair to compare a 5970 to a GTX480 when it has two smaller GPU's vs. one bigger GPU? All of these conditions are silly at best.
Here is what matters to most of us when looking to buy a graphics card.
-How does it perform?
-How much does it cost?
-Extra features, noise, heat, power, single vs. multiGPU, etc. may factor in for some people as well depending on what they are looking at.
So most of us look at how it performs vs. what our budget is, we don't care if there is 1 or 27 GPU's under the heat sink. Performance is performance regardless if it's achieved from two smaller GPU's on the PCB or one large GPU on the PCB. The common denominator for almost all of us is price. If the 5970 is significantly faster than a GTX480 and the cost is the same or very near it, then that is the better part for most of us regardless of what is under the heatsink.