Qt application runs slowly on RaspberryPi

[AUDI_ENG]

Hi,

I have finish my Qt application
I'm using a raspberryPi as device

The application consists on displaying data in a window
I have a start button, Stop button, Reset and Exit

I see that the application runs slowly, for example when I click on the stop button, I will wait a few secondes for stoping the display
Other problem : I display my data on real time, so I will see the changement of data but its not the case, I see the changement each few seconds

What do you think about the problem ?

Thank you