Formerly it was cheap taiwanese brands, with a ripped off japanese electrolyte formula that was missing an anticorrosion additive. That was the first wave of bad caps notorious on earlier boards. Now we seem to be hitting a second wave. The reasons for this lot seem to be that the reputable japanese makers got slammed for orders when the first wave hit, and consequently I think quality on some batches went down the pan, in the effort to get more out of the door. Secondly, there appear to be counterfeit Japanese brand name capacitors around, that manufacturers may have innocently used, thinking they found a source of good ones.
I was doing some research specific to the A7N8X deluxe, and a number of people seem to be having some issues and the finger has been pointed towards the caps, but I haven't seen any definitively confirmed. There is talk that the Rubycon caps used on some of them may not be as stable at higher FSBs as the versions with Nichicon caps on. However, complicating the analysis of this is the fact that counterfeit Rubycon caps have shown up, looking very similar, but actually saying "Rulycon" on them. So it's unclear whether the boards with the stability problems have had real Rubycons, and they are just a bit marginal in that application, or that they had fake Rubycons.
Also an issue on the A7N8X Deluxe is the type of RAM being used. Apparently Asus hasn't certified many modules for use on this board, and the use of anything other than the recommended ones, no matter how good a reputation they have on other boards, has had some people pulling thier hair out with reboot and instability issues.
regards,
Road Warrior
