http://www.pcgameshardware.com/aid,699312/Modern-Warfare-2-Graphics-card-benchmarks-of-the-latest-Call-of-Duty/Practice/
Considering that its a 7900GTX and the 7900GT is around the same level of the PS3 GPU my point stands. One 5870 is 8+ * more powerful than the PS3 GPU and therefore the 5970 is more than 12* more powerful.
Tease.







