@PhoenixMiner I am recently experiencing a significant slowdown on my Radeon VII cards!

OS: Arch Linux
Driver: opencl-amd 19.30.934563-1 (which is on your 'good drivers' list I think)
PhoenixMiner version: 5.2e
Algorithm/coin: Ethash/Ethereum

I used to use PhoenixMiner 4.7c which worked great up until a few weeks ago when It would not start anymore citing some DAG allocation error (on a card with a 16GB framebuffer LoL). I then switched to 5.2e and everything was well again (same MH/s).

Today I went to check on the rig and the hashrates have dropped dramatically! I tried auto-tune etc, same result. I read somewhere here that PhoenixMiner is switching to another method to allocate the DAG due to 4GB coming up shortly? Maybe this new method kicked in recently and it is more compute heavy? I am sure you know that the Radeon VII is (the only?) consumer GPU that is actually core-limited instead of memory-limited when mining ethash.

Radeon VII used to do ~92 MH/s out of the box, now it barely reaches 80 MH/s. The rigs could run stable for many months without monitoring, so having to monitor and make multiple changes in past week has been a pain. I would rather not go through the hassle of switching to another miner.