AMD RX 580 mining rig... one of the cards drops to 50% hash rate after a while

Running a four GPU RX 580 mining rig using Claymore miner. Recently build rig that has been running pretty nicely. I have 3 more GPU's but waiting for power cables to be delivered so I can hook them up.

After a few days of mining GPU 1 has dropped to a 352 h/s rate while the other cards are still getting 600+ h/s. What could cause this?

It happened once before right after I set up the rig after a couple hours of mining. I replaced the PCI-E riser and it went back to 600+ h/s. It seems unlikely that the replacement PCI-E riser would fail again??? And seems strange it would just reduce the hash rate rather than fail all together. GPU temp is being kept around 75C.

These are the risers I have:

https://www.amazon.com/gp/product/B072XGDWB3/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Two of them were somewhat dead on arrival... the power would cut off to the GPU's while the computer was starting up.

And anymore suggestions on getting the hash rate into the 700s? GPU 0 will do 650 and the other GPU's had been doing 600 to 610.

Topic: AMD RX 580 mining rig... one of the cards drops to 50% hash rate after a while (Read 135 times)