Hi Carlos,
have you tried the workaround to lock the GPU frequency?
Every time after reboot open a terminal and type:
sudo nvidia-smi -pm ENABLED
sudo nvidia-smi -lgc 1000,2000
You can put those commands in a start-up script as well to avoid typing them in every time you startup the computer.
In the second command, the lower value should hinder your card to go to P8 state (=PCIe Gen1), the higher value should be your graphics card boost frequency. Please try out and report back