AMD Cayman info (or rumor)

[informal]

That's more 35-40% informal

Um ,no.
all resolutions :
5870 90
580 112 => 112/90=1.25x

1024x768:
5870 87
580 104 => 104/87=1.19x

1280x1024
5870 89
580 111 => 111/89=1.24x

1680x1050
5870 89
580 113=> 113/89=1.27x

1920x1200
5870 91
580 115=> 115/91=1.26x

2560x1600
5870 92
580 116 => 116/92=1.26x

As I've written,25% is very doable in games . End users could care less for Synthetic benchmarks.
In the end,we get smaller chip that performs on par with 40% larger chip,while costing the same or less.