Jetson Nano slow storage writing

I have troubles running a script that write images continuously in storage on jetson nano. There are big drops in fps from time to time. When i run the benchmark from the"disk" software to test the sd card, there are huge speed drops every few seconds. I tried to write directly on a hdd via usb but same problem occurs. When i benchmark this hdd, performances are less than when i benchmark the same hdd with an other computer.

Does anybody have an idea?

Thank you in advance

Please execute sudo nvpmodel -m 0 and sudo jetson_clocks for a try. To check if running in maximum performance mode brings improvement.

I already tried but nothing changed.