I have been testing for a week with both Optiminer and Claymore and cant seem to get a stable rig with 7 GPU’s. I have been testing with two identical rigs and both have issues with GPU2 not matter how they are configured. Ubuntu 16.04 Server, Desktop, Legacy, UEFI all have same issues. I am coming to the conclusion that a 7 GPU rig is just not possible with Ubuntu. If I disable GPU2 both miners run like a dream. GPU2 is located in the last PCIe slot on both my MSI Z97 Gaming 5 MBO’s.
I am using the MSI Z97 Gaming 5 but have been focusing on Ubuntu 16.04 Server.
I discovered today that Ubuntu 16.04 desktop does install and work correctly. So clearly there are some auto configuration issues that are missing with the server version. I will try to isolate and come up with an installation process for server.
Update:
I have one rig running over 24 hours with all 7 rx-480 card (~1700 Sol/sec total) on Ubuntu Desktop 16.04 Legacy BIOS install.
The second identical rig has same issue with GPU2 dropping out and locking up the system. This rig has 4 XFX cards and not 100% Sapphire Nitro. So I can only assume… its the card?
Would not be so bad since Claymore allows a script to run triggered by the watchdog but since the GPU2 fallout causes a (sudo reboot) to hang, I cant manage this problem remotely via ssh. Looking for a stable 6 GPU configuration now since I head out of town tomorrow and once it hangs it over (i cant even shut it down remotely).
BTW: you don’t have to give Claymore root access to manage fan speed control (always a bad idea for closed software). You can change the permissions in a startup script that allow Claymore to change the fan speed without root access, much better.
Update:
Its the XFX cards. They have very poor temp control / monitoring. Cant keep 2 of them in the low 60C range so they are hitting 70C intermittently and their intensity is being cut by Claymore. I am finding I need to maintain low 60C range in Ubuntu for stability. Sapphire Nitro are sitting at ~63C stock -i 8 240 Sol/sec and very stable. XFX are intermittently hitting 70C even at 200-210 Sol/sec. Last time I buy XFX cards.
Ill try XFX cards at -i 1 and use additional air flow and see what happens.