My Gigabyte 3080 drops hashing after mining for a minute or two.
Tried changing risers and power connectors to no avail.
I have Silverstone Platinum PSU 1200 W.
The hashrate drops on both everything stock and TDP at 80 or 70 or any other value as well.
I have the same issue as you, with an RTX 3080 Gigabyte Eagle OC. Starts out at 88Mh, slowly dropping to 77Mh.
I installed the GPU straight on the motherboard. I noticed that the reason for this is that the core clock is dropping automatically to around 1000Mhz for some reason.
Also, total power consumption according to Phoenix miner is around 200W. (same thing with Claymore btw)
Did you find a solution for this problem? Thanks