1. First of all, you need to go to settings => About phone, you
will see Build number, tap on it for good 7times.
2. Now go back to the main settings, scroll down, you will
see 'Developer Option' just above About Phone.
3. Tap on Developer Option and toggle it on just at the top
right corner of your screen.
4. Now scroll down till you see these options below:
Window animation scale
Transition animation scale
Animator duration scale
Now open these settings and set them to .5x or 0.5x
depending on your phone.
Then go back and feel the speed on your Android phone.
With these, your Android phone will never Lag.