Just out of curiosity, why would a buggy, non-working (wasn't shown to work), watercooled, AIB prototype of a 3870x3 lead you to believe there will be a production 4870x3 when it didn't even mean there was a production of itself?
Derek Wilson mentioned getting a working one
and i didn't see this posted yet:
http://www.tgdaily.com/content/view/37554/135/
it is a bit of a rehash but is today's date. This did interest me:
Our sources state that the manufacturing cost of the GT200 die is somewhere between $100 to $110 per piece. It is pricey and you will be getting a lot more processing logic inside this core than with any other semiconductor part in the short history of the IT industry.