My 6-gpu rig runs fine on genoil, but in claymore one of the GPUs has 0 hashrate from the beginning, hangs in OpenCLL, claymore restarts, then the system becomes non-responsive.
Since it runs fine on genoil, I'm not sure what the problem could be?
PSU, the riser and the distribution of the power cables also can cause this. Especially pay attention on the PSU rails distribution among the VGA cards and try to move the power connectors to ensure they connect well. However some details could help: psu, vgas, risers, anything.