The 4800 series is coming in Q4 2008, so the 4600 and lower series would likely come out in H1 2009.
HD 4870 is similar to the GTX 260.
In price only. Unfortunately for NVidia, the 4870 exceeds the 260 and catches up to, and in some cases exceeds the 280. All while consuming less power under load.
And all at a substantially lower price point. You can't say two cards don't compete with each other because they are priced differently. Or because one has less memory. They absolutely compete against each other when performance is on par and one is priced considerably higher than the other.
The only thing holding the 4870 back from exceeding the 280 in every meaningful test is the lower memory available to it.
Either way, ATI is the best buy across the board, for low end and high end cards at the moment. Add in the card and chipset failures on Nvidia's part, the ridiculous price gouging and wonky drivers and it's a no brainer.
The most amusing thing is, in order to even beat the 4870X2 by single digit FPS, you have to spend $900 for an SLI setup. And if Nvidia releases another one of these hackneyed "glue to PCB's together" garbage again, ATI will just drop the 4870X2 price.
I'm not arguing for the sake of fanboyism, I'm arguing from a business perspective. It's a win-win for ATI this time around.
Unless NVidia drops the prices of the GTX cards AGAIN, since they were stupid enough to think they could price them as ridiculously as they did initially, or releases the shrunken die versions earlier, I think NVidia is a flop this round.
It's the cycle of graphics cards, it sways back and forth, as it's done for years. The next generation cards may swing back into NVidia's favor, but ignoring the painfully obvious this time around isn't going to help them accomplish anything.