Its all word play, theres no board redesign, but new ones will have certain components uprated
Exactly, if they say its been redesigned to be safer, then they open themselves up to liability with the original version.
Cards discretely dissappear, then come back in stock with marginally different parts, its called a v2.0, and the official answer if anyone asks will be something along the lines of
"yeah, the old VRM's aren't being made anymore, so we put different ones on them that are totally the same"
It comes across a little better than the real answer of
"well, for no apparent reason we thought saving £4 on components on a £500 card, then having to downclock it 30% so no one wanted one was a really really good idea, then we realised they still blew up so we've spent another £2.50 on components to stop them blowing up. Why didn't we spend the whole £4 and make a 30% faster card, and charge an extra £100 for a vastly superior card.............. "
Seriously, I don't hate the 6990, but certainly don't like it, just poor design from AMD, sticking with this ruddy awful blower fan that is really just utter tosh. Better fan, bigger fan, lower temps, higher clocks, less noise.
But the 590gtx, its laughable, theres literally not a single reason they couldn't have made it a 750Mhz per core card, none at all, they just cheaped out on it.
The PCI-E spec is a GUIDELINE, but even the guideline says triple slot and the guideline was for less power than the card uses anyway. The PCI-E guys really just say as long as the card works safely they aren't too fussed, quad slot, 600W, as long as its safe, its fine.