Hello guys.

I haven't been able to make the card hold 850mv and around 1300mhz on the core while mining,
It doesn't matter the driver used, or even using the amd radeon software as suggested. The issue is not on mem temps, but on core temps.

The card behaves as if it was overheating but only while mining, but the core is running around 65ºC with 90% fans. Checked on MSI and on amd radeon software. Only when the temp goes below 55ºC is when the card pushes a bit more on the core (around 1150 or so giving around 50mh/s). So it's basically as if the card thought it's overheating and for that reason it should undervolt itself really hard.

It's so weird because it only undervolts hard while mining. You can play games with it at full RX 5700XT core and everything ok.
It does this weird issue with every miner i tried, phoenix miner and RTM. even on different Pcs.

The final conclusion of this weird issue, seems to be that due to the aftermarket fan replacement that i had to install since the original died, maybe there is an interaction between sensors and gpu bios and the card cannot check fan correctly so assumes it's not working ok and undervolts while mining.

I know it sounds weird, but there is absolutely no explanation to this. I'm almost sure than in winter it will run as intended due to low temps in the room (now around 35ºC and around 26ºC in winter).

Since ETH is going PoS i'm not wasting more time on this, but i would gladly try something not said in this long post if someone has an idea.

Cheers.