As of now, Big navi based cards ie. 6xxx series have problem with PCI risers. You can get only 1 running which is only 16x pci slot, to get RISER card detected, one has to fiddle around. Second problem is their overclocking. HiveOS etc. have already implemented workaround , these can be done on any regular linux distro and are pretty stable. And yes, for me TRM did the job as I was not able to get phoenixminer , t-rex to detect AMD 6xxx cards n mixed rig (nvidia+amd).