Which software do you use to overclock more than 8 GPU under Windows 10 64bit fall update? Afterburner seems to be stuck at 8. Other tools even less.
Try with NvidiaInspector. The only problem I have is that I can not load saved profiles so I use MSI AB and additional overclocking programme( in my case as I have Zotac cards-Firestorm). WIth msi I oc 8 cards and with Firestorm 2 remaining. But Nvidia Inspector is able to detect >8, so if you are able to load saved profiles that will perfectly work.
No need to load profiles, just make a script, this tool can be used with the cmdline. Example with 6 cards.
%~dp0nvidiaInspector.exe -setBaseClockOffset:0,0,210 -setMemoryClockOffset:0,0,530 -setPowerTarget:0,56 -setTempTarget:0,0,90 -setFanSpeed:0,60
%~dp0nvidiaInspector.exe -setBaseClockOffset:1,0,210 -setMemoryClockOffset:1,0,530 -setPowerTarget:1,56 -setTempTarget:1,0,90 -setFanSpeed:1,60
%~dp0nvidiaInspector.exe -setBaseClockOffset:2,0,210 -setMemoryClockOffset:2,0,530 -setPowerTarget:2,56 -setTempTarget:2,0,90 -setFanSpeed:2,60
%~dp0nvidiaInspector.exe -setBaseClockOffset:3,0,210 -setMemoryClockOffset:3,0,530 -setPowerTarget:3,56 -setTempTarget:3,0,90 -setFanSpeed:3,60
%~dp0nvidiaInspector.exe -setBaseClockOffset:4,0,210 -setMemoryClockOffset:4,0,530 -setPowerTarget:4,56 -setTempTarget:4,0,90 -setFanSpeed:4,60
%~dp0nvidiaInspector.exe -setBaseClockOffset:5,0,210 -setMemoryClockOffset:5,0,530 -setPowerTarget:5,56 -setTempTarget:5,0,90 -setFanSpeed:5,60