No HD 4×90
The way ATI's branding works, Radeon 4×70 will always be the highest card in the generation and the bigger the X is, the faster the card is.
There were some rumors about Radeon HD 4×90 cards, but we can tell you that there won't be any announced, at least not for the American or European markets, while Chinese market tends to have a mind of its own.
So, the highest performing card in that generation has 70 at the end of the name, the mid range uses 50, while the entry-level part ends up with 30. It's quite logical and the bigger number is always better where Radeon HD 4870 will end up faster than current HD 3870.
