Thoughts.

z9 mini
I have my miners Hosted outside, OR direct outside air, we have been having around -15c and the miner worked great got it up to stable at 681mhz since release.
2 fans front 1800rpm rear 1640 rpm Chips temp around 28-30c  hash Avg 14.9ksols

Today the weather Drastically changed to +2c and i got all 3 boards xxxx

seems that it was the bm1740_verify_nonce_integrality CRC error. Reebooted but only took like 7min then got the same error again.
But after that ive only been able to maintain 656mhz.

soon as i go above that i loose one board.

CAN it be possible that the colder the chips can be maintained the higher mhz we can maintain? I never tried above 681mhz