Appmiy App Monitor is ideal to find out the device CPU and memory resources state in real time.
It has 2 main options:
It shows a graphic and several text labels wherein the values of the CPU and memory usage are updated every 0.5, 1, 2 or 4 seconds.
It can record on a CSV file the read values for a later usage and process on a spreadsheet program.
The app can run in the background. Then, the second option is specially interesting since, in the background, Appmiy App Monitor consumes little resources and can monitor and record the CPU and memory values that other applications are using in the foreground.