The monitor program can display detailed technical information about your computer. Select the menu item Window > Show system info or press ⌘ + 4.
The section Computer contains the name of the system as you have defined it (which may not be identical to the name used to identify this computer in the network), Apple’s official model name (also known as marketing name), a short description and a picture of this model series, the Apple model identifier which is the code Apple and macOS internally use to identify this series, the computer’s serial number, its unique hardware identification, and the week of production.
The second section Processor lists details about the processor configuration, as well as the available cache sizes. This includes the official processor model identification, the vendor identification, the number of processors, available processor cores and active cores, the information whether each core is capable of executing multiple threads of instructions (Simultaneous Multi-Threading, if active, the hardware will simulate twice the number of processors), the processor generation specifier for x86 systems which includes the family number, model number, stepping number (hardware version), and the decimal signature which compresses all identification code into one single number, the processor’s main clock frequency, the sizes of the level 1 caches (I for instructions, D for data), and the sizes of the level 2 and 3 caches.
The section Memory shows the size of physical memory (Random Access Memory, RAM) currently built into your computer and the optimum free size. This size specifies the small amount of physical memory the operating system should try to keep free for best performance. The optimum is reached when no RAM is wasted (nearly everything is in use), but a small remainder is left free for current handling. The line Addressable memory defines the size of physical and virtual memory the processor can internally manage. This does not mean that this amount could actually be used in practice. The number of slots available for memory modules and other limitations of the computer’s chipset will reduce these theoretical values.
The fourth section Logicboard contains detail data about the computer’s main logic board, namely the vendor information, its internal model code, and its serial number. This section also shows the version number of the System Management Controller (SMC) and its firmware. The SMC is an auxiliary processor which manages the computer’s internal sensors and its power management features. It operates the “always-on” parts of the system, still running when the actual computer is in sleep mode or shut down. It is also responsible to identify the computer as genuine Apple-branded product, constituting the main difference between a generic personal computer and a Macintosh.
The last section Operation Environment summarizes the version information about the computer’s firmware, the Darwin operating system on which macOS and iOS are based, the kernel version and revision codes, as well as the operating system version and build numbers.
If your computer has a built-in system management database compliant with industry standards, pressing the button Show management records will open a second detail panel with other types of information (see below).
The detail sheet on computers containing a system management table has the following information available:
These management records are not computed by Hardware Monitor but only retrieved by it. They have been stored by the manufacturer into the so-called System Management BIOS area of the system’s firmware when the computer was assembled. Some parts are also computed dynamically by macOS by retrieving the necessary data from the available hardware.
You can also get detailed information about the battery used if using a portable Mac. Select the menu item Window > Show battery info or press ⌘ + 5.
Voltage: The voltage currently supplied by the battery, or being used to charge it, respectively.
Current (Amperage): The current supplied by the battery at the moment, or being used to charge it. Some batteries represent discharging currents by a negative, charging currents by a positive number. You can influence this by a preference setting.
Temperature: The temperature currently being measured by the battery within the battery unit. The temperature unit can be controlled by a preference setting.
Current charge: The remaining capacity estimated by the monitoring processor of the battery, describing its current charge state. In addition to the reading in milliampere-hours, the value will also be shown as percentage and as colored bar.
Charger connected: This status display allows you to see if the AC adapter of the computer—which is also the charger of the battery— is currently connected.
Charging: This status display will indicate “yes” if the battery is being charged by an attached power supply.
Running on reserve: Indication whether the system should warn the user that not much energy is left.
Charge cycles: The number of complete charge and discharge operations that have been performed during the lifetime of this battery. The monitoring processor in the battery unit determines what is considered to be a complete cycle. The number of charge cycles is one of the main factors influencing wear and tear of the battery.
Maximum capacity: The capacity the battery can hold in its current state when it is fully charged. This reading decreases with advancing age. It is an estimate computed by the processor within the battery unit. By calibrating the battery, the estimate will become more accurate.
Original capacity: This is the maximum capacity this battery has been designed for. The battery had this capacity when it came straight from the factory. The relation between maximum and original capacity is additionally shown as percentage and as colored bar. For brand-new batteries, this value can temporarily grow above 100%. In this case, the battery can store more energy as it has to, according to specifications.
Cell voltages: The battery is in fact made up of multiple battery cells, which can be arranged in parallel or serially. These actual batteries and the monitoring processor form the battery unit. Depending on design, each unit can contain between 1 and 4 individual cells. The voltage of each cell is shown numerically and by a colored bar.
Current computers use battery cells based on lithium ion technology. Under load, the voltage of a cell will be between 3.3 and 3.8 volts, depending on cell type. The maximum charge voltage of a fully charged cell is approximately 4.2V. Under optimal circumstances, the behavior of all cells of a battery (including their voltages) should be equal, because they have been constructed identically. A worn-out or defective battery can often be detected by a voltage of one cell differing significantly from the voltages of the other cells, because this cell is no longer capable of performing according to its specifications.
Beginning with the 10th generation of the MacBook Pro (the 15-inch MacBook Pro with Retina display, released in June 2012), Apple has started to add innovative features to their battery units. You should keep in mind that a few technical details show a slightly different behavior for the latest built-in Apple batteries:
Depending on your computer and the version of macOS it is running, the operating system might monitor the correct function of all connected hard disks to predict whether a disk drive could fail. This function is based on a feature called S.M.A.R.T.
S.M.A.R.T. is the abbreviation of Self Monitoring, Analysis, and Reporting Technology. It is an industry standard introduced in 1992 to react earlier on hard disk failures. A hard disk supporting the S.M.A.R.T. standard monitors itself with its own micro processor and allows the operating system to request information if technical parameters have changed in such a way that the hard disk might become defective in the near future. In this case the hard disk can be replaced before any data is lost.
S.M.A.R.T. is available for all up-to-date hard disk drives that are connected via a SATA or PCI interface. To display the current status of your drives select the menu item Window > Show Drive Overview or press ⌘ + 8.
The columns in the table have the following meaning:
The table does not update automatically because continuous monitoring would slow down all drives. If you want to make sure the table is up-to-date, close, then reopen the window.
The application can try to identify all displays currently connected to the system. Select the menu item Window > Show Display Info, or press ⌘ + 9. The following data about each display unit should become accessible:
The amount of information provided will vary between different display vendors. This feature will not work with monitors built before 1995. In case you are using a display cable not compliant with VESA standards, or the signal is routed through a switch or similar device, neither macOS nor Hardware Monitor may be capable of identifying the display.
If multiple displays are connected, you can switch between them using the buttons in the upper right corner. When connecting or disconnecting cables for external monitors, you should close and reopen the information window to ensure you are getting up-to-date information. An example is shown in the following picture:
Display units directly built into Apple computers usually identify themselves as “Color LCDs” built by ‘APP’ (Apple Inc.).