ETH mining with Claymore - sudden drop in hashrate

[schilling2k]

Hello guys,

I have been seeing a sudden ~35% drop in hashrate on my 4 mining rigs during the last couple of days from ~28MH/sec per card to about 18MH/sec.

I am using 4 identical rigs, with this setup:
- Ubuntu 16.04
- amdgpu-pro-17.40-483984
- Claymore's Dual Ethereum+Decred_Siacoin_Lbry_Pascal AMD+NVIDIA GPU Miner v10.4
- 5 RX 470 cards Radeon Nitro+ 8G

Nothing has changed in my setup, e.g. software updates, HW changes,... It has been working fine for several weeks - apart from having to reboot the rig every now and then - before the sudden drop. It started with 2 of the 4 rigs, now all 4 are affected.
Any idea what could have caused this?

Best Regards & Thanx!