How to Reset SMC and PRAM/NVRAM on a Mac Tower

Edited 2 days ago by ExtremeHow Editorial Team

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Macs are known for their reliability and smooth operation, but sometimes, users may encounter problems such as unexpected shutdowns, problems with display settings, or other configuration-related glitches. When faced with such problems, one of the first troubleshooting steps is often to reset your Mac's System Management Controller (SMC) and PRAM/NVRAM. These resets can clear up various oddities and return your Mac to proper functionality.

Understanding SMC and PRAM/NVRAM

Before considering how to reset these components, it is worth understanding what SMC and PRAM/NVRAM are and what role they play in the functioning of your Mac tower.

What is SMC?

The System Management Controller (SMC) is a subsystem responsible for low-level operations on Intel-based Macs. It is a microcontroller that manages various components, including:

• Power Management – Controls sleep mode, wake function, and shut down.
• System Performance - oversees performance and thermal management, i.e. cooling fan operation and CPU performance.
• LED Indicators – Manages the status lights and other indicator LEDs.
• Battery Management - Monitors charging and battery status.
• Other functions – Overseeing functions such as keyboard backlighting and ambient light sensing.

What is PRAM/NVRAM?

PRAM (parameter RAM) and NVRAM (non-volatile random-access memory) are similar in purpose. They are small storage areas where your Mac saves essential settings before the operating system loads. These include:

• Volume Settings
• Display settings – resolution and colour depth
• Startup disk selection
• Time zone information
• Information on recent kernel panics (if any)

Specifically, while both are related to storing settings, PRAM is traditionally used more in older Macs, while NVRAM is used in newer models. For the purpose of this discussion, the term NVRAM will refer to the functionalities of both PRAM and NVRAM.

When should you reset the SMC and PRAM/NVRAM?

Resetting these controllers isn't a solution to all Mac problems, but it can be crucial in solving some hardware-related or settings-oriented issues. For example, you might want to reset the SMC when:

• Computer fans are running too fast and noisy, even when the machine is not being used much.
• Your Mac isn’t responding properly or won’t boot up properly and won’t wake up from sleep.
• The battery is not charging properly or the battery indicator is functioning erratically.
• Keyboard backlighting does not work as expected.

Resetting the PRAM/NVRAM can be useful when:

• There are problems related to sound settings, such as incorrect volume levels.
• The display resolution is incorrect, or there are abnormalities in color depth.
• Your Mac doesn’t boot from the correct startup disk.
• The system time is incorrect because the time zone setting is off.

Steps to reset SMC on Mac tower

The method for resetting the SMC varies slightly depending on the specific model of your Mac. Here, we focus on Mac towers, specifically Mac Pros, which represent a significant subset of Apple's desktop line-up.

Process:

1. Shut down your Mac: Make sure your Mac Pro is completely shut down. Choose "Shut Down…" from the Apple menu in the upper-left corner or press and hold the power button until it shuts down completely.
2. Disconnect the power cord: Unplug the power cord from your Mac Pro. Keep it unplugged for about 15-20 seconds.
3. Wait for a while: After unplugging, wait for a while (about 30 seconds to 1 minute) to ensure that any remaining power is drained from the electrical components.
4. Reconnect the power cord: Reconnect the power cord to your Mac Pro.
5. Power up your Mac: When the power cord is securely connected to your Mac Pro, turn it on by pressing the power button.
6. Observe and verify: Evaluate your Mac's performance after an SMC reset to make sure the original problems are resolved.

Steps to reset PRAM/NVRAM on a Mac tower

Process:

1. Shut down your Mac: Similar to the SMC reset process, start by shutting down your Mac Pro.
2. Locate the keys: Identify the "Option", "Command", "P" and "R" keys because you will need to press them simultaneously.
3. Turn on your Mac: Turn on your Mac. As soon as the startup sound comes on, immediately press and hold the "Option + Command + P + R" keys simultaneously. Keep holding them down.
4. Press and hold for 20-30 seconds: Hold these keys down for about 20-30 seconds. During this period, your Mac may restart, the screen may flash, or you may even hear a second startup chime on older Mac models.
5. Release the keys: After the required time has passed, release the keys and allow your Mac tower to boot normally.
6. Check the settings: Once your Mac has successfully booted, go to "System Preferences" and review and adjust any settings that can be reset, such as the display resolution, sound levels, or any other preferences you typically set.

Conclusion

In short, both SMC and PRAM/NVRAM resets are fairly simple procedures but can be potentially highly effective in resolving a number of problems associated with Mac computers. Particularly when dealing with hardware setting and performance-related issues, these resets serve as quick interventions before more in-depth troubleshooting.

After performing these resets, you will find your Mac running more smoothly and efficiently. Still, keep in mind that if problems persist beyond SMC and PRAM/NVRAM resets, it is advisable to explore other troubleshooting steps or consult an Apple technician for further diagnosis and repair.

Whether you're an experienced Mac user or new to the Apple ecosystem, understanding how to perform these resets is essential as a maintenance tool in your troubleshooting arsenal. Despite their inherent simplicity, their impact can sometimes be profound, restoring your Mac's functionality and optimizing its performance with minimal hassle.

Remember that technology is not infallible, and devices can have troublesome moments. However, with a good understanding of fundamentals such as SMC and PRAM/NVRAM reset, you are better equipped to handle such situations effectively.

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