No Connection to Kernel Frequently

Currently using Ultra96v2 with PYNQ 2.5. The USB ethernet connection is really slow, and besides that, I often lose connection to Python kernel while notebook is open. I usually only keep 1 notebook running at a time. What might be the issue? Anybody experience anything similar? Any help will be greatly appreciated.

If everything turns out to be very slow for you, it might be the SD card issue. I used to see that, but after I replaced a new SD card, it came back to the normal speed.

Thanks for the response. I got a new card and it definitely helped.