Sudden drop in hashrate?


Hi All - My rig has been stable at 87MH/s for several weeks with no issues, I have 3xASUS RX470’s and 1xGigabyte RX480 all currently stock BIOS. I have has some trouble trying to update the BIOS but lets not get into that just yet.

I am running Ubuntu 16.04 with Ethminer, today at around 12pm my rig suddenly dropped to 66MH/s and has been stuck at that since then?

Has anyone else experienced this problem and if so why? I read on another forum that it could be related to an update for the Intel processors however why would this affect the GPU’s?

If anyone has any information or assistance to offer me it would be really appreciated