I'll be interested to see how both of your are doing in the next couple of weeks. Most GPU's start throttling at 80C in terms of performance but who knows how these will hold up.
I've never actually got any of my GPUs to 80C, but like I said before @ 750mhz / 60-65C I got about 2000 Sols/s more than when I was @ 750mhz / 80-85C.
One person in this thread has reported theirs died inside within a couple of days of extreme overclocking but you hear that about every version of Bitmains miners, there are always a few that have immediate or near immediate failures.
I don't think he was doing anything extreme like increasing the voltage. I think he just ran it at 700mhz or 750mhz. It is likely there was something wrong with his miner or a heatsink was not attached properly.
I guess it could be argued how much more profitable the miner could be at 15-16 vs 12-13k vs power usage. at 575Mhz mine are running under 66C with fan set on auto and between 12.5-12.8K, haven't pulled power usage at this speed though.
Mine at stock speeds was only pulling 265 watts with a bronze 750 watt PSU. At 750mhz I'm pulling just over 300 watts.
The net result for ~3k additional hashrate is running the chips at 10-15C hotter and who knows what power usage... I'm wondering if its worth it if the miner dies in the short term (under 90 days).
I just want to break even on this thing. Making a profit after cost of machine + electricity would be great. Right now at today's network hash/diff and prices I'll break even in 75 days given what I have already mined.