How to Clear and Free Up RAM Memory on iPhone and iPad
The steps to free up RAM space on iDevice is different to hard or soft reboot, and it is useful especially for old-generation iDevices with 1 GB or less RAM running the latest versions of iOS firmware.
Step 1. To start, hold down the Power button on your iDevice till you see the message “slide to power off” on the screen.
Step 2. Don’t cancel, and avoid sliding the button to switch off the device.
Step 3 After the “slide to power off” message appears on the screen, release the Power button, and hold down the Home button for a few seconds until the screen flashes black and go back to the Home screen.