Non-Volatile Random-Access Memory (NVRAM) is a small amount of memory that your Mac uses to store certain settings and access them quickly. These settings include information about the startup disk selection, speaker volume, screen resolution, and recent kernel panic information. Resetting the NVRAM can be a useful troubleshooting step if you're experiencing issues with your Mac, such as problems with sound, display settings, or even startup issues.

In the Apple environment, NVRAM is equivalent to what is known as BIOS settings in Windows PCs. Resetting the NVRAM can help resolve various hardware-related issues by clearing and resetting these stored settings.

Examples:

1. Resetting NVRAM on Intel-based Macs:

   1. Shut down your Mac.
   2. Turn it on and immediately press and hold these four keys together: Option (⌥), Command (⌘), P, and R.
   3. Keep holding the keys for about 20 seconds. During this time, your Mac might appear to restart.
   4. Release the keys.

   After resetting the NVRAM, you might need to reconfigure some settings like speaker volume, display resolution, and startup disk preferences.

2. Resetting NVRAM on Apple Silicon Macs:

   Apple Silicon Macs (such as those with the M1 chip) handle NVRAM differently, and there is no need to manually reset it. Instead, you can reset all settings by using the following method:

   1. Shut down your Mac.
   2. Press and hold the power button until you see the startup options window.
   3. Select "Options," then click "Continue."
   4. Follow the onscreen instructions to access macOS Recovery.
   5. Once in Recovery mode, go to the "Utilities" menu and select "Terminal."
   6. In the Terminal window, type the following command and press Enter:

      nvram -c

   7. Restart your Mac.