Android GUI Lagging

I have an android 4.4 kitkat loaded on my sd card (sdhc class 10), and a GUI loaded with different apps such as to monitor sensor values and to control the GPIOs of the beaglebone black amongst many other apps, but my GUI keeps on lagging on the Touchscreen panel which is a dell (S2240T).

I have kept the clock speed at 1 GHZ of my BBB.

What do I do to avoid this lagging?

Thanks,