I have 10 of these cards and have been running for 4 months now. Only one so far

has had a fan die on it. They run around 75C and haven't shown any signs of dying. I do need to dust them off though.

Have you gpus with SN such as A13510002XXXX or A135000034XXX? These cards with these SN, no working in my case more than 3 months 24/7.
RMA with Sapphire is very slow, more than 3 weeks and two of my dead gpus haven't been repaired yet (they said me that the problem isn't identified yet)