Mac 101: How to Verify If Your Mac’s Hardware Is Working Properly

We only check our devices whenever we notice unusual activity or they perform unsatisfactorily. Rarely do we take the time to check our computers and other devices for issues and the problem with checking your computer only when you notice a problem is that sometimes, it’s already too late.

Understand that every computing device, may it be your desktop computer, laptop, or mobile phone, consists of both hardware and software components. And if you are a Mac user, you’re probably under the impression that you have a very secure and reliable machine, think again because while this is true for the most part, a lot of things can still go wrong with your device’s components. All you need to keep in mind is that just because everything seems to be running smoothly, it does not necessarily mean that everything is problem-free.

Before You Begin: An Important Reminder

With this article, we will guide you to performing a Mac hardware test that checks to verify if your Mac’s hardware components are all working correctly, even if it’s not showing any signs of problems but bear in mind that testing your Mac for hardware errors can put stress on your system. It’s imperative that you have one or more backups of your computer so you can recover all of your data if any of it gets lost during the process. We also suggest scanning your Mac through Mac repair app first, to reduce junk files and get an extra RAM boost.

The First Step: Apple Diagnostics

Apple Diagnostics is a built-in utility available for Macs introduced in June 2013 and later. This is mainly designed to help determine which specific hardware component may be needing attention. To get started, launch Apple Diagnostics by doing the following:

• Disconnect all external devices aside from the mouse, keyboard and display (for Mac desktops), Ethernet connection (if applicable), and AC power connection.
• Make sure your Mac is on a flat, stable, and hard surface. Make sure the area has sufficient ventilation.
• Shut down your computer.
• Once completely turned off, turn your Mac on again.
• Immediately press and hold D on your keyboard. Keep holding the key until the option to select language appears.
• Use the navigation/arrow keys on your keyboard to select your language, then press Return/Enter.
• If you don’t have an Ethernet connection, you might be asked to connect to a Wi-Fi network if the diagnostic image can’t be pulled itself. However, the system may automatically connect to a known and secure network, and this step will be skipped altogether if you do have an Ethernet connection.
• Once the language is successfully selected, testing will begin.
• The diagnostics will run for 2 to 3 minutes.
• You will get either a “No issues found” message or a list of issues with their corresponding codes. Take note of the reference codes before you proceed.
• At this point, you can choose to “Run the test again” by pressing Command + R; get more information, including service and support options, by clicking “Get started” or pressing Command + G; restart your Mac normally by clicking Restart or pressing R; or shut down your Mac by clicking Shut Down or pressing S.

If your test came back with issues and reference codes, you could cross-reference the codes with the codes on this list. Only by checking the meaning of the codes will you know what to do next. Some will tell you to rerun the test, contact Apple Support, or take your Mac to the nearest Apple Store or Apple Service Provider for assistance.

Furthermore, for devices launched before June 2013, use the Apple Hardware Test instead, which is basically the older version of Apple Diagnostics*. Launching this also follows the same procedures as with launching Apple Diagnostics. But after the language selection, the test will not automatically run. You need to click the Test button.

*Apple Diagnostics and Apple Hardware Test are basic and generic tests. You can also perform other tests that target specific hardware components.

Checking the Hard Drives (HDD/SSD)

As you use your Mac, you create different types of files and data and save them on the hard drive. While Mac’s hard drive is made sturdy and highly capable of doing its job, it is bound to fail sooner or later due to years of use.

Some of the most common symptoms of hard disk failure are computer slowing down, freezing, strange noise, and corrupted data. But many users tend to ignore these symptoms, especially when restarting the unit usually seems to solve the problem.

Fortunately, you won’t have to wait before your hard disk completely breaks down. Every hard drive uses S.M.A.R.T. or the Self-Monitoring, Analysis, and Reporting Technology. You can check your hard drive’s S.M.A.R.T. status to know if it’s doing fine or already failing. In a previous article, we discussed in detail what S.M.A.R.T. status and how to check for it on a Mac.

By running the standard check on your Mac, you will get two basic results: verified or failing. A verified status means your drive is in excellent condition, while a failing state should be enough to encourage you to back up your computer immediately and most probably, get a replacement. And there’s another way to interpret S.M.A.R.T. data. You can use third-party programs, such as SMART Utility and DriveDx, to look into specific of S.M.A.R.T. data. And while they are installed on your Mac, the apps can give you warnings regarding changes in the hard drive’s health and show you more advanced info about the state of your hard drive.

Checking the Memory or RAM

Now, here’s where it gets tricky. When testing the unit’s RAM, you’d want as little of it in use during the test. However, your computer already uses several GBs of your RAM and when you test your Mac, only the portion not used by the OS will be examined. Better than nothing, though, right? Aside from using Apple or Mac Diagnostics, you can use two other utilities to check your RAM’s status.

• Rember – This is a small utility that has a simple interface. With this utility, instead of typing commands in the Terminal to activate the memory testing tool called Memtest OS X, you can run the test with just a click of a button. Rember allows you to specify the amount of RAM to test, as well as the number of times to run the test.
• Memtest86+ – Memtest86 is actually based on Rember, but it has other options. To run this test, you need to first create or burn the pre-compiled ISO image on a disc or flash drive. Then, you need to boot up the Mac using that bootable image. When starting up the Mac, press and hold C to boot from the disc or drive. Don’t be intimidated by the interface, though. Even though it’s text-based, making it look primitive, memtest86+ is a potent and accurate one. Since you will boot your Mac from an external drive, little to no RAM is used so most of it will be available for testing. Memtest86 will test your RAM with different algorithms. If your RAM survives these tests, then it’s in absolutely good shape.

Checking the Processor or Central Processing Unit (CPU)

Your CPU essentially works in sync with your RAM, so while testing the RAM, the CPU also had a workout. However, some tests specifically target CPUs and processors.

• Benchmarking – In this testing method, the CPU performance is tested using a range of algorithms. Benchmark utilities, such as Geekbench, throw the CPU a certain amount of data to process under the varying algorithms. Since the tests are short, we suggest that you restart the test a couple of times within an hour to see how good the CPU is at handling a semi-continuous workload. In the end, you will have a benchmark score, which you can compare with other Macs that have the same specs as yours. This way, you will know if your Mac’s CPU is performing as expected from its class.
• Stress testing – These tests aim to really push your CPU to its limit, putting it under stress that it probably won’t go through in real-world conditions. If you’re worried that these tests might unnecessarily wear out your Mac’s CPU, know that it’s okay not to do them. But if you’re interested to know its real capacity, you might want to try the “Yes” test. In this test, the CPU is given a command that elicits the response “yes” over and over again, until it makes the CPU run at 100% utilization.

Checking the Graphics Card or GPU (Graphics Processing Unit)

Contrary to common notion, the graphics chip or card doesn’t only work for games. It’s responsible for showing practically everything you see on your Mac. Without the graphics card, you’ll be staring at a blank screen. MacOS relies on the GPU to render visuals, windows, and effects. Your Mac’s GPU works as hard as your CPU, primarily when you usually perform visual-intensive tasks. If you rely a lot on your Mac’s GPU power, it’s best if you’d perform a GPU test to see if yours can keep up with your needs. Here’s how to test a GPU:

• Benchmarking – Yes, you’re reading this right. GPU tests are similar with CPU tests, only that the tools to be used are different. Just like with CPU benchmarking, the tests for GPU are also short, so you’d have to run them again and again to gather sufficient and accurate results. Some of the excellent programs for GPU benchmarking are Cinebench, LuxMark, and Geekbench.
• Stress testing – Just like in CPU stress testing, this will involve putting your GPU to excessive work. This means throwing a sizable workload at it for an extended period of time. For this, the best program to use is Heaven, which is technically a benchmark tool. Heaven is different from others in a way that it can be set to put maximum pressure on the GPU. Heaven tests the GPU by rendering game scenes at quality and resolution that you will specify during setup. Since Heaven is a benchmark tool, the tests will also be short, so you have to restart every test to get a few loops.

Checking the Sensors

The sensors in your Mac are among the most difficult to accurately test at home. While there are utilities that can test the sensors, only Apple really knows the correct value ranges to determine if a sensor passes the test or not. Basically, when you run Apple Diagnostics, and the result didn’t note any problem, it means that your Mac’s sensors are working just fine. But if you want to take a closer look into how your Mac’s sensors are doing, you have some options. The top tool for reading the different sensors on your Mac is TechTool Pro. This test has quite a comprehensive system that includes the testing of temperature, voltage, current, power, and light sensors.

Checking the Physical or External Aspects of Your Mac

Of course, when we talk about hardware, we don’t talk about what’s inside alone. Hardware also includes the ports, keyboard, and optical drive. Testing these are pretty easy.

To test the ports (USB, FireWire, and headphone jack), just connect the external devices and wires to the ports to verify if they are working fine. For older Macs that still have an optical drive, see if it can read a CD or DVD. Meanwhile, to test the keyboard, just directly open a TextEdit file and test every key in your keyboard. You can also use Mac’s built-in Keyboard Viewer tool. Open System Preferences > Keyboard. Check “Show keyboard and emoji viewers in the menu bar.” The option “Show Keyboard Viewer” should now be available in the menu bar. Click on that, then press the keys on your keyboard. If the keys register with a gray color, then they are working as they should.

Checking the Cooling System

There’s no tool that tests Mac’s cooling system explicitly yet, but if you’ve used your Mac to extreme benchmarking and stress testing without it overheating or crashing, then it’s a good indicator that its cooling system is very much capable. Indeed, your Mac is a complex system made up of various components that work well to make sure that the entire system works well.

We hope that this article gave you an idea on how to verify if your Mac’s hardware components are in excellent condition, and help you take care of your computer better.