That is 176F and I am far below it at 153F. To me this seems OK then? Even at 832 clock and 163F this is still well below 176F.
far below?? well below?? Seriously, all that is given is that the chip hasn't fried itself, just yet. Good luck! You are operating at the edge of it's operating range, and while 153F is within limits by all accounts it is seriously hot. 176F is not a safe operating limit, but a potential fry and die limit. You also have to be aware of changes in ambient temperature, if the ambient rises, so goes the chip temp. In general, even if it runs, you will shorten lifespan if it gets that hot over long time.
So why do I need another fan? I cannot go above 832 clock as I get too many hardware errors (over 10%) on these even cranking up the core voltage.
When you are overclocking you are on your own, and you want to do everything reasonable to keep the babies alive. Alive==cool. 832 == overclocking. But yeah, it's not that you MUST have cooling. But you should! jstephanop wrote a good comment on this a few pages back, when one guy had 8 MLDs running at 5.5Mh/s or thereabout. You should read it. I run at 924Mhz with about 0.7%HW and ca 45C core. AND extra cooling (usb fans). Some ppl remove the stock fans --> you are on your own, even at normal clockspeeds. 10% is way too high at normal clockspeeds. You should have less than 1% at 600Mhz.