There is a difference between performance mode and performance levels. Performance mode  0 is "prefere maximum performance" mode 1 is "adaptive" and 2 is "auto". Performance level is the thing with the clock speeds(adaptive clocking)1 to 4, witch you can see in the gui. It looks like a by design "feature" from the nvidia driver. Everytime you start the miner software the performance level goes to 3 and the card clock will go down. Overclocking settings will also effect the clock speed on a lower perfomance level.
Example : level 1   200mhz  and 400mhz
                  level 2   400mhz and 100mhz
                  level 3   1200mhz and 3000mhz
                  level 4    1700mhz and 4000mhz
After overclocking gpu +100 memory +1000 it will look like this:
                  level 1   300mhz  and 1400mhz
                  level 2   500mhz and 1100mhz
                  level 3   1300mhz and 4000mhz
                  level 4   1800mhz and 5000mhz
The only thing you do with overclocking, is making your card clocks speed as fast as it should be.
It would be super if someone has a solution for that.
Btw nvidia-smi -ac 5000,1800 won’t work in my case.(application clocking)

There is also a post at the nvidia devforum with the same problems.