How do I monitor CPU temperature?

Excessive heat damages electronics. Monitoring the temperature of your CPU and other computer components can help you keep them running properly. To properly use most software of this type, you will need to ensure you have ACPI functionality enabled in your motherboard BIOS.

Monitor CPU Temperature

Why is CPU Temperature so Important?

When the first affordable PCs were offered to the general public in the early 80's, system engineers and designers took in consideration what heat was emitted by system components and ensured their case and cooling designs handled the appropriate amount of heat so system damage or instability was rarely an issue. These PCs were not very configurable, and could not easily be modified or customized by the end user, except for memory limits and number of floppy storage devices. Most peripherals were external, so they didn't really add heat issues to the base system, and those that were internal were low power, and low bandwidth technologies. This was acceptable to the public at the time, because people didn't have the basic knowledge and skill sets required to customize or modify their PCs.

During the 90's when there were many huge advances in microprocessor, bus, and solid state electronics as a whole, the original offerings were altered. More vendors were offering peripherals and computer components tailored to specific user needs and requirements, the system manufacturers started to recognize that there was a significant market in aftermarket sales of specialized peripherals, and the technology to produce smaller and faster processing solid state electronic components really took off. More system capabilities were integrated into the system motherboard without increasing its size, including high fidelity sound, high speed I/O buses and memory buses, as well as new technologies like DMA transfers and shared memory systems. New advances in operating systems that were multi-user and multi-processing started to be available for the desktop PC market. Systems were becoming more capable, and more customizable as time went on. Unfortunately, there was a price, additional cooling was required to keep the system stable. As larger power supplies were installed to handle the additional components, and solid state circuitry got smaller and smaller, the heat output from major and even minor components was increasing significantly. At the same time, users wanted smaller and smaller cases to recover some of their desk and floor space.

In the late 90's, the temperature bubble burst. New high performance components were becoming more and more simple to integrate into an existing system, the vendors producing motherboards were creating more flexible designs allowing users to add more capabilities without buying a new system, and the biggest change of all, high quality graphics capabilities were coming onto the market. Users were really customizing their PCs to a great extent, modifying the system to meet their specific goals and needs, where only the hard core users would even consider doing this in the past. Heat was increasing by leaps and bounds in these systems.

Semiconductor Companies Producing Sensor Chips

Nearly complete information on sensing products, including documentation for APIs and other software interactions and data sheets are available from vendor web sites. The most prominent players in the sensor market are:

How Do You Poll Sensor Circuits to Display Environment Data

As a user, normally you would use your systems BIOS configuration menus, or install monitoring software. As a developer, you would develop software using APIs that are developed to interact with system BIOS or the various system buses on your machine. Sensor controls are almost always connected to the PCs IDE bus or SMBus infrastructures, and can be accessed using the standard APIs for those buses.

What is Overclocking and Overvolting

Overclocking is the process of turning up the processor clock or multiplier value of a processor unit on the motherboard, attempting to get the highest possible clock and multiplier value without compromising system stability. Modern processors are often multiplier locked, preventing a user from just changing the bus multiplier and introducing negligible additional heat to the system. Only the actual processor clock value can be changed on these CPUs, generally having a wider effect on system heat and stability.

Overvolting is a necessary evil for modern processors, and is generally used to attempt to stabilize an overclocked processor that is proving to be unstable. The voltage tolerances for microprocessors today are reasonably wide, around 10% or more. Increasing the voltage values gives the processor more juice to ensure that its logic gates are handling decisions reliably. A significant side effect of overvolting is heat emission.

Overclocking and Overvolting your systems can have negative effects on the life span of your system, so be sure you know what you are doing when you attempt them. Attempting to overclock and overvolt your system also has a chance of permanently damaging your hardware.



Processor and Memory Overclocking and Overvolting and Heat Emission

Customizing a PC to meet new processing requirements is a never-ending battle. Power users are hoping to eek every last bit of performance out of their current system so that upgrades aren't nearly as common, and so they can run the most current software with the least amount of investment. The primary i386 processor manufacturers were releasing newer and faster processors, but they were never pushed to their limits in consideration for system stability. Sure, in some cases like the famed Intel Celeron 300A, the processor clock could be doubled without additional cooling requirements, but this was rare. Overclocking by more than 10% of the clock without having stability issues due to heat was a rare treat. At this point it was still a cat and mouse game, the user would buy motherboards that would allow them to overclock and overvolt their components (ASUS, and ABIT were the first reliable and popular developers of these kinds of components, and are still very prevalent today), check system stability, and if it failed you stepped the values down. If the system was stable, the user would step up the settings. Of course, cooling solutions were significantly more affordable than new major system components, and more and more third party vendors were trying to fill in the cooling gap, but there still wasn't a method to properly monitor your system's environmental settings preemptively.

First Generation Monitoring Solutions: Monitoring Temperature in System Bios

Many PC motherboards now contain hardware monitoring circuits which are able to measure temperature, voltages, and fan speeds. Most modern motherboards also allow you to configure alerts, alarms and actions to take based on specific temperature and fan settings. Your system's environmental conditions can be displayed when viewing the details in the bios setup screens, but this doesn't help you once your system is running your preferred operating system.

Second Generation Monitoring Solutions: Monitoring Temperature in Software

The first generation of CPU temperature monitoring software packages merely displayed the CPU temperature value. No alarms, events, or actions could be defined, it was merely a display only technology. If action was required the user would have to notice that the temperature was at a critical state, and have to do something about it. If the user wasn't watching, the system could easily overheat and cause system damage. Unfortunately, users aren't always at the console all day looking at temperature values, so this was only useful during diagnostics and testing periods when technicians knew there was a likelihood for temperature issues. It did help significantly with testing and burn-in periods, but beyond this, it was mostly just a data point a user might poll for a piece of mind.

Some sensor circuits have the ability to regulate and control environmental conditions automatically, so that second generation solutions are adequate enough to keep your system stable when heat is an issue, and quiet when it isn't.

Third Generation Monitoring Solutions: Hardware that Allows Software to Monitor and Modify State

The newest generation of CPU temperature monitoring software interacts directly with motherboard sensor and fan control circuits to attempt to control and adjust the system environmental conditions. Many of the motherboard manufacturers offer this software for free (Abit's microguru and Asus' PC Probe), because they are specifically targeting the custom and high performance system builders. In fact, Abit has an excellent LCD panel that you install in a 5.25" 1/2 height drive bay that allows you to monitor and even control your processor and environmental settings using a simple button interface!

Third Party Monitoring Software

Not all motherboard vendors provide software to display and control system environmental resources. Even when they do, sometimes the software is functional, but poorly developed, clunky, unreliable, or may not play well with other installed system software. Aside from this, not all vendors use the same sensor solutions on their boards, or between multiple boards they produce. Also, many motherboard vendors don't put as many fan controller connections as you would prefer to have in your system, so you may want to install a fan controller card or additional environmental control components that are outside of your motherboard's control. To cope with this, many software developers have been providing software solutions to give you an integrated control solution.

Most monitoring software will automatically detect and configure the proper sensors for your motherboard. Some have a drop down list of motherboards that you can select from, and others simply has a drop down list of motherboard sensors to select from. If you have questions about which motherboard sensors your motherboard has, check your motherboard or system documentation, or contact your system vendor.

Free Windows CPU Temperature Monitoring Software

Second Generation Monitors:

  • Motherboard Monitor is an excellent program that handles a wide variety of motherboards and sensors, but is no longer in development. Since the package will never be released open-source, as time goes on, it will be less and less usable. Thanks for your efforts, Alex van Kaam!

  • If you have an Intel motherboard or motherboard based on an Intel Chipset, such as the Intel P35 Chipset, you can utilize the Intel Active Monitor.

Third Generation Monitors:

Most third generation monitor packages are only available through motherboard manufacturers at this point, but a few third party packages are available for download.

  • SpeedFan is a freeware program that monitors voltages, fan speeds and temperatures in computers with hardware monitor circuits. What really sets SpeedFan apart is that it can change fan speeds (if supported by your computers hardware) according to the temperatures measured inside your PC. SpeedFan makes it possible for you to run your PC as quietly as possible, while also running it safely.

  • Hmonitor is really a cross breed between second and third generation monitoring software. If you purchase the professional version of the software can preempt a change in CPU frequency or fan speed based on an event.

Free Linux CPU Temperature Monitoring Software

Linux has had a few effective temperature monitoring packages out there for the last few years. Although the knowledge and skill requirements to install and configure the software, someone who spends a little bit of time researching the packages and determining their needs should have little trouble getting the packages to work properly. Most of these packages require a recent release of the Linux kernel.

Second Generation Monitors:

  • lm-sensors has the capability to detect, display and configure monitoring parameters for your Linux system.

  • If you want to monitor many system resources at a glance, or control how the display of that data is provided, you might check into GKrellM. GKrellM is just a visual framework for the environmental control functions of Linux, so you will need to have previously install "lm-sensors" to get it fully functional.

  • KSim is a package that combines the sensing capabilities of "lm-sensors" with the visual controls of "GKrellM". KSim is a plugin based system that lets you monitor and display only those components you feel are important.

Third Generation Monitors:

An integrated third generation application for system sensor monitoring and control has not been released to the public as of yet, but there are some alternatives if a user has the proper amount of motivation, knowledge and communication with the Linux developer community.

  • The Sourceforge ACPI Project is an ACPI framework and utilities set for Linux that can be used to monitor and control system environmental resources.

Free FreeBSD CPU Temperature Monitoring Software

FreeBSD has an application in its ports system that will allow you to monitor your onboard sensors.

Second Generation Monitors:

  • lmmon is an ncurses based application that samples sensor status every second, and displays it on the screen. The software can be configured to output simple text so it can be utilized by system management and alerting systems like the NET-SNMP package or other external programs.

Apple OSX CPU Temperature Monitoring Software

Apple Computer has always led the industry in providing the user's low level controls and details on their hardware that most manufacturers would consider unnecessary, and even foolhardy. Apple has continued this practice by providing access more hardware monitoring sensors that other comparable systems provide. So far, all software releases for monitoring on OSX are second generation solutions.

Second Generation Monitors:

  • If you are only concerned about temperature sensors in your OSX system Temperature Monitor is a freeware application that will monitor and display all temperature related systems on your computer. If you want to monitor and display non temperature related sensors, you can purchase the full version of the software Hardware Monitor.

Conclusion

Modern users want to control and customize their systems to a greater degree today than ever before. Because of this, monitoring your systems sensor resources is critical for helping make what was previously a tedious, time consuming and technically challenging possible for the every day user.

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