I'm new to mining world and still working on stability of the rig
I have 4 GPUs RX570 AORUS 4GB with samsung memory attached with 4 raisers 006c to an old motherboard (3 gpus on pci-e 1x and one gpu on pci-e 16x)
Gigabyte EP45-UD3LR v. 1.0
E5300 with x6 multiplyer at 1.25v (for lower power consumption)
80GB SATA HDD
PSU Seasonic 850W Gold
windows 10 professional 64bit
robinh00d's blockchain driver
Mining on ethermine
BIOS mod with UBER Mix 1 timings from 1500 to 2000
So, here is my problem. My cards go weel over 2100 and even one of them work stable (with no errors) on 2180 the others max 2130-2150, but from time to time I got seriously low hasrates like 16 and 17 for one,two or even 3 cards, then on the next job they appear again with 31-31.5MH/s This cause alot of drops and ups in my graphic and my average drops to 115-116 which is about 29 on each card (this is measured in long term, like 24 hours and more)
Currently I'm running them with the following settings:
-mclock 2120 -cclock 1180 -mvddc 975 -cvddc 850 -dcri 6
And have put them to work for a certain time.
Is it possible to have this problem because of the motherboard? Or it is normal?
Do I overclock them correct with these settings or I'm trying to destabilize them intentionaly?
What cause this drops?