Why after any flashing, Android tablet (Samsung P6200) slows down?

Question

Android

Brakes the tablet wildly. Flashing does not help. I took flashing from w3bsit3-dns.com.
Pretty old tablet, with a wide charging connector. I once unsoldered the connector and soldered the USBmicro connector instead.
TWRP installed on the tablet.
Constantly heated, but at the same time you can wait 1 minute to minimize the desktop.
At the same time, from GApps (GAppsNano) there are only youtube, playmarket.
The tablet does not seem to be a laptop, it does not have heat pipes, it is an ordinary aluminum plate. but it also sticks tightly to the CPU. And in general, on a pure Android, it should not get warm, even if the aluminum plate is not tight.

Answer 1

First, find the culprit - turn on the display of the processor load in the settings (there is everywhere, in the developer section) and find out which process is loading.
Google apps already carry an enviable piece of garbage and loads on the computer, maybe they are downloading and installing something at this time? and on the old machine you have to wait for hours (when you turn off the process is interrupted and after that it starts again)