Why would any other cards than the 590 be damaged? The 590 was the only card that did not have working ocp using that driver.
They did mess up, they assumed that ocp was working with the driver that came with the box, but you need ForceWare 267.71 for that.
If it was a power issue, why did not the same psu kill the rest of the cards when they used the newer driver?
They found out from nvidia that the ovp did not work in that driver.