Have been reading the official underclocking documentation on these, but it's fairly sparse about what you can actually expect to get from the huge range of frequency settings available. Basically I'd be interested in finding the absolute best W/GH these can produce.

One thing that I can't find any more information about is the 2x Mode mentioned in the manual other than that it's only available with voltage indexes of 4 or above. I even used an archive to search the old BFL forums, but nothing about it there either. Is it actually worth messing with? Does it double performance or some such?

Thanks!