Question Massive hash-rate drops on Gigabyte RTX 3090 Gaming OC when mining ?

[SuPanda]

Hi guys,

So I recently decided to mine on my gigabyte rtx 3090 gaming oc and the first week everything was fine and I had constantly a hashrate of 120 mh/s but gpu memory temp was getting quite hot (110 C) so yesterday I decided to put some thermaltape, heatsink and a 3000rpm fan on the backplate of the card and while that helped with the gpu memory temp (around 94-96 C now and gpu core around 42 C) it made my hashrate extremely unstable, like one minute I'm at 120 mh/s and next minute it drops all the way down to 35 mh/s. I know that thermal throtteling with rtx 3090 starts at 110 C and a few days ago i had a much more stable hashrate despite the higher memory temps.

I'm aware that replacing thermal pads on the card can help a lot with gpu memory temps but i like to avoid that since I have nevet done something like this before and there is a chance of breaking your gpu + my warranty will be gone. Also yesterday after adding the heatsink and fan on the backplate I started getting some BSODS like this Machine_Check_Exception and have a hard time getting booting up the windows sometimes.

So I'm not quite sure what's going on here ? My guess is that there is still some part of gpu overheating while mining and there isn't any sensor on it and it causes these weird hashrate drops ? If that's the case maybe changing the stock thermal pads on the card is my only option then ? But even then it still doesn't explain the machine check exception bsods I'm getting. Any advice/tips is much appriciated & Thanks !

Some additional info:
I'm mining ethereum using T-rex miner and using ethermine.org for mining pool. I have tried other mining softwares and pools and same hashrate drop is happening. Also when the hashrate drop is happening I noticed my gpu core clock goes up a little and reaches 1400mhs even tho it was locked at 1200mhz and when the hashrate drop is gone the core clock goes back to 1200mhz

 

[Dredd84]

Hey, the 3090 has 24gb vram and it is dual sided on the pcb, so cooling it is really a headache, it's a design fault from the manufacturer. Eth mining is memory intensive, and gddr6x memory heats up more than normal. Ive sold all my 3090s and replaced them with 3080s. You can do the same or will need to replace the thermal pads on the pcb, backside and front, check a YouTube video and you should find that your pcb will be missing some thermal pads most of the time, I've had it on my 3080 gaming oc as well. Adding a heatsink with fan is good but won't do much if the heat is unable to be absorbed from pcb to thermal pad to metal backplate. Once you open the card, you will most probably find most of the thermal pads missing, you might actually kill the card if you don't do the pad replacement..