Performance Scaling with OCZ's 8800 GTX
 

How does performance scale up when you increase the GPU of the G80 GTX core? Anandtech finds out:

"The F.E.A.R. graph looks a little more disturbingly discrete, but it is important to note that the built in benchmark only provides whole numbers and not real average framerates. Again, for the most part, performance increases keep up with the percent increase in clock speed. This becomes decreasingly true at the higher end of the spectrum, and this could indicate that extreme overclocking of 8800 GTX cards will have diminishing returns over 660 MHz.

http://www.anandtech.com/video/showdoc.aspx?i=2931&p=1