Still thinking about a potential driver issue... Because the default adapter always stays at 99% load while the two others go down, then up, than down... like that. Anybody mining on ubuntu 12.04? If so, what driver version are you using?
you might think it's driver but i'm calling Power on this one, either drawing though the PCIe or just right on out of the Kingwing !
your PSU says 1000W right? you know a KingWing isn't going to Run 1000W - you are running 3x cards and a mobo, and a HD?
cya later KingWing, likely the draw on the Pcie is too much , also does it outright just freeze sometimes?
if so that's power , its happened to me , how i actually tested it was to turn my vacume on , it acted like it was drivers , but its a power draw issue.
that's my best guess,
pull one card out and see if it still does it , (or have you done that already? )
so just run two , see what happens.