3) I use X Server to check GPU's overlocking. And there is core clocks looks like in MSI Afterburner (1800-1900Mhz for gtx 1070), but memory clocks are too large (8900-9000Mhz, MSI Afterburner displays 4400Mhz for same GPUs). Such big memory clocks is ok for ubuntu? Any other soft for checking Overlocking?
Linux take a different approach on Memory Clock, its double the value of what you use in windows.
Google it and read more about it
If you are on 1.4 you can see your rig error logs in webinfo too
rigip/index.html