Hi everyone,
the pclocks printings of nvidia-smi are wrong in my case - however nvidia-settings shows it right.
user@debian:~$ nvidia-smi dmon -s pucmt -d 1 -o T
#Time gpu pwr temp sm mem enc dec mclk pclk fb bar1 rxpci txpci
#HH:MM:SS Idx W C % % % % MHz MHz MB MB MB/s MB/s
18:58:43 0 108 33 49 21 0 0 4303 112 790 5 1844 276
user@debian:~$ nvidia-settings -q GPUCurrentClockFreqs
Attribute ‘GPUCurrentClockFreqs’ (debian:0.0): 2111,4303.
user@debian:~$ uname -r
4.9.0-2-amd64
Board: GTX 1070
Regards to all.