In MSI afterburner, I have set the fan at 100% manually to test it but same results. The hashrate drops to 70-85 MH/s fluctuating frequently.
I removed the card from rig frame set it aside and I have just put a table fan at high speed near the card and have cold/fresh air blowing on it. Looks stable for an hour+ now. But I guess this is not the solution. ~97 MH/s now.
I purchased it from a local online retailer, and they do not have any more stock to replace the card it seems.
It's weird, if the card is hashing normally now you can conclude that is a temperature problem
If you already tested with fans at 100%, another thing that could be are the thermal pads, can you check if thermals are in touch with heat pipe?
Or maybe the position of the card in your rig, is there hot air blowing direct to this card?