Can you confirm what type of device you are using?
Have you confirmed the device is currently up to date with the latest software?
Have you attempted to wipe the system cache partition recently?
- Press and hold the Power key, tap Power off, and then tap OK.
- Press and hold the Power key and Up Volume key at the same time.
- Release the Power key when the Samsung logo appears.
- Release the Volume keys when the Android image appears.
- Press the Volume keys to highlight the Wipe cache partition.
- Press the Power key to select.
- Once “Cache wipe complete” appears, press the Power key to select Reboot system now.
- The device restarts once the wipe is finished.
Also, try testing your device in safe mode to see if the screen still lags.
This step will temporarily disable all your third-party apps, but none of your personal data will be deleted. Your customization settings (Wallpaper, Themes, et cetera) will be reset to default once you exit this mode.
Please follow the steps below:
1. Turn the device off.
2. Press and hold the Power key past the model name screen.
3. When "SAMSUNG" appears on the screen, release the Power key.
4. Immediately after releasing the Power key, press and hold the Volume down key.
5. Continue to hold the Volume down key until the device finishes restarting.
6. Safe mode will display in the bottom left corner of the screen.
7. Release the Volume down key when you see Safe Mode.
8. To exit Safe Mode, restart your device.
If your screen does not lag in this mode, which means a third-party app may be causing this to happen. I recommend deleting each individual third-party app until the symptoms do not occur anymore.