The problem with Anand's benches is that they baseline the results from their first (and often only) review of the card. So like back in the day when the 7970 was released on rubbish drivers the performance of it was shown up against later released nvidia cards when in reality the two cards performed almost identically on more recent drivers.
The same is true this time round. The 780 has been out for a long time and there's been at least a couple of notable driver improvements since then so the performance shown on the Anand bench facility is no longer relevant. Indeed the 290/X has also seen improvements so basically it's a case of finding a review where the two have been both benched recently.
With respect to the two cards in question they perform almost identically so it's the other things you look at such as reliability, faults, additional features, cost etc.
The same is true this time round. The 780 has been out for a long time and there's been at least a couple of notable driver improvements since then so the performance shown on the Anand bench facility is no longer relevant. Indeed the 290/X has also seen improvements so basically it's a case of finding a review where the two have been both benched recently.
With respect to the two cards in question they perform almost identically so it's the other things you look at such as reliability, faults, additional features, cost etc.