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In August 1908, a white mob attacked Springfield, Illinois’s Black community, destroying homes and businesses and lynching two Black men. National outrage over the violence helped spur the movement that created the NAACP the following year.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
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Underclocking, also known as downclocking, is modifying a computer or electronic circuit's timing settings to run at a lower clock rate than is specified. Underclocking is used to reduce a computer's power consumption, increase battery life, reduce heat emission, and it may also increase the system's stability, lifespan/reliability and compatibility. Underclocking may be implemented by the factory, but many computers and components may be underclocked by the end user. Underclocking is the opposite of overclocking.
For microprocessors, the purpose is generally to decrease the need for heat dissipation devices or decrease the electrical power consumption. This can provide increased system stability in high-heat environments, or can allow a system to run with a lower airflow (and therefore quieter) cooling fan or without one at all. For example, a Pentium 4 processor normally clocked at 3.4 GHz can be "underclocked" to 2 GHz and can then be safely ran with reduced fan speeds. This invariably comes at the expense of some system performance. However, the proportional performance reduction is usually less than the proportional reduction in clock speed because performance is often limited by other bottlenecks: the hard disk, GPU, disk controller, network, etc. Underclocking refers to alterations of the timing of a synchronous circuit in order to lower a device's energy needs. Deliberate underclocking involves limiting a processor's speed, which may affect the speed of operations, but may or may not make a device noticeably less able, depending on other hardware and desired use.
Many computers and other devices allow for underclocking. Manufacturers add underclocking options for many reasons. Underclocking can help with excessive heat buildup, because lower performance will not generate as much heat inside the device. It can also lower the amount of energy needed to run the device. Laptop computers and other battery-operated devices often have underclocking settings, so that batteries can last longer without being charged.
In addition to providing underclocking features, manufacturers can choose to limit the capability of a machine in order to make it more efficient. Reduced instruction set computer (RISC) models can help makers build devices that work on less power.
Underclocking can also be performed on graphics card processor's GPUs, usually with the aim of reducing heat output. For instance, it is possible to set a GPU to run at lower clock rates when performing everyday tasks (e.g. internet browsing and word processing), thus allowing the card to operate at lower temperature and thus lower, quieter fan speeds. The GPU can then be overclocked for more graphically intense applications, such as games. Underclocking a GPU will reduce performance, but this decrease will probably not be noticeable except in graphically intensive applications.
Newer and faster RAM may be underclocked to match older systems as an inexpensive way to replace rare or discontinued memory. This might also be necessary if stability problems are encountered at higher settings, especially in a PC with several memory modules of different clock speed. If a PC processor is underclocked, and the clock factor or multiplier (the ratio between the processor and the memory clock speed) is unchanged, the memory will also be underclocked.
Dynamic frequency scaling (automatic underclocking) is very common on laptop computers and has become common on desktop computers as well. In laptops, the processor is usually underclocked automatically whenever the computer is operating on batteries. Most modern notebook and desktop processors (utilizing power-saving schemes like AMD's Cool'n'Quiet and PowerNow![1]) will underclock themselves automatically under a light processing load, when the machine BIOS and the operating system support it. Intel has also used this method on numerous processors through a feature called SpeedStep. SpeedStep first appeared on chips like the Core 2 Duo and selective Pentium models, later becoming a standard in mid to high-end Core i3, i5, and i7 models.
Some processors underclock automatically as a defensive measure, to prevent overheating which could cause permanent damage. When such a processor reaches a temperature level deemed too high for safe operation, the thermal control circuit activates, automatically decreasing the clock and CPU core voltage until the temperature has returned to a safe level. In a properly cooled environment, this mechanism should trigger rarely (if ever).
There are several different underclocking competitions similar in format to overclocking competitions, except the goal is to have the lowest clocked computer, as opposed to the highest.[which?][citation needed]
In general, the power consumed by a CPU with a capacitance C, running at frequency f and voltage V is approximately[4]
The Linux kernel supports CPU frequency modulation. In supported processors, using cpufreq to gain access to this feature gives the system administrator a variable level of control over the CPU's clock rate. The kernel includes six governors by default: Conservative, Ondemand, Performance, Powersave, Userspace and Schedutil.[5] The Conservative and Ondemand governors adjust the clock rate depending on the CPU load, but each with different algorithms. The Ondemand governor jumps to maximum frequency on CPU load and decreases the frequency step by step on CPU idle, whereas the Conservative governor increases the frequency step by step on CPU load and jumps to lowest frequency on CPU idle. The Performance, Powersave and Userspace governors set the clock rate statically: Performance to the highest available, Powersave to the lowest available, and Userspace to a frequency determined and controlled by the user. The Schedutil governor estimates the load through the scheduler's Per-Entity Load Tracking (PELT) mechanism.
Underclocking can be done manually in the BIOS or with Windows applications, or dynamically using features such as Intel's SpeedStep or AMD's Cool'n'Quiet. In Windows 7 and 10, underclocking can be set within the "advanced" settings of a power management plan.[6][7]
Earlier models of the Asus Eee PC used a 900 MHz Intel Celeron M processor underclocked to 630 MHz.
Underclocking can be performed in the EFI.
Most smartphones and PDAs, such as the Motorola Droid, Palm Pre, and Apple iPhone, use underclocking of a more powerful processor, rather than the full clocking of a less powerful processor, to maximize battery life. The designers for such mobile devices often discover that a slower processor gives worse battery life than a more powerful processor at a lower clock rate. They select a processor on the basis of the performance per watt of the processor.[8]
The performance of an underclocked machine will often be better than might be expected. Under normal desktop use, the full power of the CPU is rarely needed. Even when the system is busy, a large amount of time is usually spent waiting for data from memory, disk, or other devices. Such devices communicate with the CPU through a bus which operates at a much lower bandwidth. Generally, the lower the CPU multiplier (and thus clockrate of a CPU), the closer its performance will be to that of the bus, and the less time it will spend waiting.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
Underclocking, also known as downclocking, is modifying a computer or electronic circuit's timing settings to run at a lower clock rate than is specified. Underclocking is used to reduce a computer's power consumption, increase battery life, reduce heat emission, and it may also increase the system's stability, lifespan/reliability and compatibility. Underclocking may be implemented by the factory, but many computers and components may be underclocked by the end user. Underclocking is the opposite of overclocking.
Transistor aging (sometimes called silicon aging) is the process of silicon transistors developing flaws over time as they are used, degrading performance and reliability, and eventually failing altogether. Despite the name, similar mechanisms may affect transistors made of any kind of semiconductor. Manufacturers compensate for this (as well as manufacturing defects) by running chips at slower speeds than they are initially capable of (underclocking).
Double data rate synchronous dynamic random-access memory (DDR SDRAM) is a type of synchronous dynamic random-access memory (SDRAM) widely used in computers and other electronic devices. It improves on earlier SDRAM technology by transferring data on both the rising and falling edges of the clock signal, effectively doubling the data rate without increasing the clock frequency. This technique, known as double data rate (DDR), allows for higher memory bandwidth while maintaining lower power consumption and reduced signal interference. DDR SDRAM was first introduced in the late 1990s and is sometimes referred to as DDR1 to distinguish it from later generations. It has been succeeded by DDR2 SDRAM, DDR3 SDRAM, DDR4 SDRAM (1×32-bit channel), DDR5 SDRAM (2×32-bit subchannels), and upcoming DDR6 SDRAM (with 4×16-bit subchannels), each offering further improvements in speed, capacity, and efficiency. These generations are not backward or forward compatible, meaning memory modules from different DDR versions cannot be used interchangeably on the same motherboard. In 2026, a cost-reduced HUDIMM was introduced, with only one 32-bit channel, not the usual two subchannels (and thus also half the bandwidth and capacity of DDR5), compatible with some DDR5-using motherboards. Another adaptation to skyrocketing memory prices (caused by AI boom) are adapters to use cheaper laptop memory in desktop computers. DDR memory is used in laptops, desktops and servers, in different (DIMM) form factors; and usually unbuffered, not registered, except in servers. CUDIMM is a desktop memory (form factor) introduced for DDR5 in 2024, clocked (and unbuffered), while registered memory exist (for servers), and faster DDR5 MRDIMM; and generation 2 and 3 of MRDIMM upcoming). DDR SDRAM typically transfers 64 bits of data at a time. Its effective transfer rate is calculated by multiplying the memory bus clock speed by two (for double data rate), then by the width of the data bus (64 bits), and dividing by eight to convert bits to bytes. For example, a DDR module with a 100 MHz bus clock has a peak transfer rate of 1600 megabytes per second (MB/s).
Intel Corporation is an American multinational technology company headquartered in Santa Clara, California. It designs, manufactures, and sells computer components such as central processing units (CPUs) and related products for business and consumer markets. Intel was the world's third-largest semiconductor chip manufacturer by revenue in 2024 and has been included in the Fortune 500 list of the largest United States corporations by revenue since 2007. It was one of the first companies listed on Nasdaq. Intel supplies microprocessors for most manufacturers of computer systems, and is one of the developers of the x86 series of instruction sets found in most personal computers (PCs). It also manufactures chipsets, network interface controllers, flash memory, graphics processing units (GPUs), and other devices related to communications and computing. Intel has a strong presence in the general-purpose and gaming PC market with its Intel Core line of CPUs and Intel Arc series of GPUs. Intel was founded in 1968 by engineers Gordon Moore and Robert Noyce, along with investor Arthur Rock, and is associated with the executive leadership and vision of Andrew Grove. The company was a key component of the rise of Silicon Valley as a high-tech center, and was an early developer of static (SRAM) and dynamic random-access memory (DRAM) chips, which represented the majority of its business until 1981. Although Intel created the world's first commercial microprocessor chip—the Intel 4004—in 1971, it was not until the success of the PC in the early 1980s that this became its primary business. During the 1990s, the partnership between Microsoft Windows and Intel—known as Wintel—shaped the PC market, solidifying Intel's position. As a result, Intel invested heavily in new microprocessor designs in the mid-to-late 1990s, fostering the industry's rapid growth. During this period, it became the dominant supplier of CPUs, and was known for aggressive and anti-competitive tactics in defense of its position, as well as tensions with Microsoft over the PC industry's direction. Since the 2000s and especially the late 2010s, competition from AMD has reduced Intel's dominance and market share, though it continues to lead the x86 market in the 2020s by a wide margin.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Mae Jemison, aboard Space Shuttle Endeavour in 1992.
