The x1900 had a load power cunsumption of 110-120 watt. The 7950 has a load power consumption of ~230. The size of the cards are also way larger. 1.5 years is not gonna fix that.
As Play4Fun said cooling systems are expensive. A proper air cooling system uses copper and copper price has not become cheaper. Actually it's the opposite.
The numbers don't add up.







