What Is NVRAM on a MacBook?
When using a MacBook for business purposes, it's essential to keep it running as smoothly as possible. Part of keeping your computer operating at its best is adjusting the settings to optimize its performance. If you change settings in system preferences, such as the audio volume or the screen resolution, but they don't save, you may need to reset the NVRAM.
The nonvolatile RAM, referred to as NVRAM on current Intel-based MacBooks was previously referred to as the parameter RAM or PRAM on PowerPC Macs. Despite the difference in nomenclature, the two types of RAM both serve a similar purpose; they store settings information that remains in place even after you restart your computer. The reason for this is straightforward; imagine how frustrating it would be if every day you turned on your computer to start working and the first thing you had to do was reconfigure all the settings. NVRAM allows you to avoid this potential headache.
What NVRAM Stores
The NVRAM stores information, such as speaker volume, display settings and EFI boot data, which determines your startup disk location. For example, the audio volume from your speakers remains at the same level you previously set it. This is beneficial if you plan to give a business presentation using your laptop and don't want to fiddle with the volume settings as co-workers idly stand by.
Differences Between PRAM and NVRAM
Former owners of PowerPC-based Macs may recall PRAM. Similar to NVRAM, PRAM stores settings configuration data. However, PRAM stores far more settings than NVRAM, such as application font data, autokey rate and port configurations. Depending on the specific model of MacBook you have, the NVRAM stores different information. To determine exactly what is stored in your NVRAM, open the Terminal application and type “NVRAM –p” without the quotes. Your computer displays all the settings stored in the NVRAM.
When to Reset the NVRAM
Despite a widely held misconception, resetting the NVRAM isn’t going to significantly speed up your computer. There are steps you can take to troubleshoot a sluggish machine but zapping the NVRAM isn’t one of them. Resetting the NVRAM is an appropriate step when you’re having trouble with settings stored in the NVRAM, such as display settings, audio settings or boot disc locations. In some cases, resetting the NVRAM can also resolve kernel panics.
How to Reset the NVRAM
To reset the NVRAM, go to the Apple menu and select "Shut Down." Power your computer back on and simultaneously hold down “Cmd-Option-P-R.” The computer should power on and immediately restart, alerting you with a second startup tone. If your computer powers back on without restarting, hold down the keys more quickly after restarting your computer. After the computer beeps twice, you can release the keys. When your computer powers on, you'll need to reconfigure your audio volume, display resolution and possibly your date and time preferences.
Logic Board Battery Issues
The logic board battery allows the NVRAM to store your settings. If, after resetting the NVRAM and reconfiguring your settings, issues persist with settings stored there, your logic board battery may need replacement. This battery is separate from your computer’s main battery and should only be replaced by a technician at an Apple Store or Apple authorized service provider. If you attempt to replace the battery, you could damage your logic board and void any existing warranty.
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