Overclocking to die's intended potential

[blackjackedy]

I was considering overclocking my 5850 but decided against it because its already quite a step u from the 9400gt I'm used to using. I did have a thought though, which was that to my knowledge a 5850 is essentially a 5870 with roughly a tenth of the die disabled and lowered clocks, and assuming this is true, wouldn't it mean that you can oc pieces to their intended potential (in this situation 5850 to 5870) without any adverse side effects as the piece is actually meant to run at that speed anyway. Are the pieces slightly faulty, therefore re-badged as a lesser models, or are they in fact the exact pieces which have been underclocked?

 

[jsc]

GPU's are subject to the kind of variations that CPU's are. Therefore, they can be binned for speed. And parts of a chip can be deactivated for one reason or another.

 

[blackjackedy]

Is there a way of finding out the reason that your piece was binned or you just gotta hope?