you could be right. however an OC'd ant is drawing about 400 watts to have a 500w PSU at 80% of it's limit is no bueno. by crobar, i meant to push it beyond its limits or to failure. my 1300 PSU turned out to be faulty (blown cap). the 600 still works well, just not well with my ant. that has been my experience...YMMV.
It's not a matter of whether I'm right or wrong. I was merely stating facts together with sound numbers to back it up.
An 80% load is still acceptable and seems to be the consensus threshold of maximum load especially for a 24/7 operation. However, I'm curious about how you equated 400WAC draw at the wall to represent an 80% load on a 500WDC PSU with an efficiency of 85%. Perhaps, you're confusing AC wattage (at the wall) with DC wattage of the PSU and vice versa and not figuring in the efficiency factor on top of that.
maybe i am wrong, i was under the impression that if you hook up a kill-a-watt meter to your device and if it indicates that the draw is 400w and if you have it hooked up to a 500w rated psu, does that not equate to a 80% load ? on a different note, one of my chains in the UI is showing my chips have gone bad. no bueno. i am only hashing at a little over 300gh/s. arrgh =(
It doesn't work that way though. A PSU (ATX, wall wart, power brick -- a.k.a. AC/DC power adapters) converts AC to DC and a certain amount of energy is wasted (produces heat) during the conversion process which determines its efficiency, hence the efficiency ratings.
An S3 overclocked to 243.75M and powered by a Corsair CX500 draws 413WAC at the wall (29C ambient room temperature). Based on the
Corsair CX500 80 Plus Verification and Testing Report, it is around 84% efficient at 75% load. Therefore, the S3 requires 347WDC (413WAC * 84%) from the CX500's single +12V rail (PCIe) which has a maximum wattage of 456WDC (38A) as indicated on its label. The load exerted on the CX500's single +12V rail would then be 76% (347WDC / 456WDC * 100). I hope this helps.
I'm sorry that one of your blades stopped hashing. Try going through the troubleshooting procedure that had been posted in here (check PCIe power connection/orientation, controller cables, etc.).