Overclocking
This article possibly contains original research. (February 2023) |
In computing, overclocking is the practice of increasing the clock rate of a computer to exceed that certified by the manufacturer. Commonly, operating voltage is also increased to maintain a component's operational stability at accelerated speeds. Semiconductor devices operated at higher frequencies and voltages increase power consumption and heat.[1] An overclocked device may be unreliable or fail completely if the additional heat load is not removed or power delivery components cannot meet increased power demands. Many device warranties state that overclocking or over-specification[2] voids any warranty, but some manufacturers allow overclocking as long as it is done (relatively) safely.[citation needed]
Overview
The purpose of overclocking is to increase the operating speed of a given component. Normally, on modern systems, the target of overclocking is increasing the performance of a major chip or subsystem, such as the main processor or graphics controller, but other components, such as system memory (RAM) or system buses (generally on the motherboard), are commonly involved. The trade-offs are an increase in power consumption (heat), fan noise (cooling), and shortened lifespan for the targeted components. Most components are designed with a margin of safety to deal with operating conditions outside of a manufacturer's control; examples are ambient temperature and fluctuations in operating voltage. Overclocking techniques in general aim to trade this safety margin by setting the device to run in the higher end of the margin, with the understanding that temperature and voltage must be more strictly monitored and controlled by the user. Examples are that operating temperature would need to be more strictly controlled with increased cooling, as the part will be less tolerant of increased temperatures at the higher speeds. Also base operating voltage may be increased to compensate for unexpected voltage drops and to strengthen signalling and timing signals, as low-voltage excursions are more likely to cause malfunctions at higher operating speeds.
While most modern devices are fairly tolerant of overclocking, all devices have finite limits. Generally for any given voltage most parts will have a maximum "stable" speed where they still operate correctly. Past this speed, the device starts giving incorrect results, which can cause malfunctions and sporadic behavior in any system depending on it. While in a PC context the usual result is a system crash, more subtle errors can go undetected, which over a long enough time can give unpleasant surprises such as
At this point, an increase in operating voltage of a part may allow more headroom for further increases in clock speed, but the increased voltage can also significantly increase heat output, as well as shorten the lifespan further. At some point, there will be a limit imposed by the ability to supply the device with sufficient power, the user's ability to cool the part, and the device's own maximum voltage tolerance before it achieves destructive failure. Overzealous use of voltage or inadequate cooling can rapidly degrade a device's performance to the point of failure, or in extreme cases outright destroy it.
The speed gained by overclocking depends largely upon the applications and workloads being run on the system, and what components are being overclocked by the user; benchmarks for different purposes are published.
Underclocking
Conversely, the primary goal of underclocking is to reduce power consumption and the resultant heat generation of a device, with the trade-offs being lower clock speeds and reductions in performance. Reducing the cooling requirements needed to keep hardware at a given operational temperature has knock-on benefits such as lowering the number and speed of fans to allow quieter operation, and in mobile devices increase the length of battery life per charge. Some manufacturers underclock components of battery-powered equipment to improve battery life, or implement systems that detect when a device is operating under battery power and reduce clock frequency.
Underclocking and undervolting would be attempted on a desktop system to have it operate silently (such as for a home entertainment center) while potentially offering higher performance than currently offered by low-voltage processor offerings. This would use a "standard-voltage" part and attempt to run with lower voltages (while attempting to keep the desktop speeds) to meet an acceptable performance/noise target for the build. This was also attractive as using a "standard voltage" processor in a "low voltage" application avoided paying the traditional price premium for an officially certified low voltage version. However again like overclocking there is no guarantee of success, and the builder's time researching given system/processor combinations and especially the time and tedium of performing many iterations of stability testing need to be considered. The usefulness of underclocking (again like overclocking) is determined by what processor offerings, prices, and availability are at the specific time of the build. Underclocking is also sometimes used when troubleshooting.
Enthusiast culture
Overclocking has become more accessible with motherboard makers offering overclocking as a marketing feature on their mainstream product lines. However, the practice is embraced more by
Overclocking offers several draws for overclocking enthusiasts. Overclocking allows testing of components at speeds not currently offered by the manufacturer, or at speeds only officially offered on specialized, higher-priced versions of the product. A general trend in the computing industry is that new technologies tend to debut in the high-end market first, then later trickle down to the performance and mainstream market. If the high-end part only differs by an increased clock speed, an enthusiast can attempt to overclock a mainstream part to simulate the high-end offering. This can give insight on how over-the-horizon technologies will perform before they are officially available on the mainstream market, which can be especially helpful for other users considering if they should plan ahead to purchase or upgrade to the new feature when it is officially released.
Some hobbyists enjoy building, tuning, and "Hot-Rodding" their systems in competitive benchmarking competitions, competing with other like-minded users for high scores in standardized computer benchmark suites. Others will purchase a low-cost model of a component in a given product line, and attempt to overclock that part to match a more expensive model's stock performance. Another approach is overclocking older components to attempt to keep pace with increasing system requirements and extend the useful service life of the older part or at least delay purchase of new hardware solely for performance reasons. Another rationale for overclocking older equipment is even if overclocking stresses equipment to the point of failure earlier, little is lost as it is already depreciated, and would have needed to be replaced in any case.[3]
Components
Technically any component that uses a timer (or clock) to synchronize its internal operations can be overclocked. Most efforts for computer components however focus on specific components, such as,
Computer processors generally are overclocked by manipulating the CPU multiplier if that option is available, but the processor and other components can also be overclocked by increasing the base speed of the bus clock. Some systems allow additional tuning of other clocks (such as a system clock) that influence the bus clock speed that, again is multiplied by the processor to allow for finer adjustments of the final processor speed.
Most
Any given component will ultimately stop operating reliably past a certain clock speed. Components will generally show some sort of malfunctioning behavior or other indication of compromised stability that alerts the user that a given speed is not stable, but there is always a possibility that a component will permanently fail without warning, even if voltages are kept within some pre-determined safe values. The maximum speed is determined by overclocking to the point of first instability, then accepting the last stable slower setting. Components are only guaranteed to operate correctly up to their rated values; beyond that different samples may have different overclocking potential. The end-point of a given overclock is determined by parameters such as available CPU multipliers, bus dividers, voltages; the user's ability to manage thermal loads, cooling techniques; and several other factors of the individual devices themselves such as semiconductor clock and thermal tolerances, interaction with other components and the rest of the system.
Considerations
There are several things to be considered when overclocking. First is to ensure that the component is supplied with adequate power at a voltage sufficient to operate at the new clock rate. Supplying the power with improper settings or applying excessive voltage can permanently damage a component.
In a professional production environment, overclocking is only likely to be used where the increase in speed justifies the cost of the expert support required, the possibly reduced reliability, the consequent effect on maintenance contracts and warranties, and the higher power consumption. If faster speed is required it is often cheaper when all costs are considered to buy faster hardware.
Cooling
All
Stock cooling systems are designed for the amount of power produced during non-overclocked use; overclocked circuits can require more cooling, such as by powerful
Water cooling carries
Other cooling methods are
Submersion cooling, used by the
Amateur overclocking enthusiasts have used a mixture of dry ice and a solvent with a low freezing point, such as acetone or isopropyl alcohol.[13] This cooling bath, often used in laboratories, achieves a temperature of −78 °C (−108 °F).[14] However, this practice is discouraged due to its safety risks; the solvents are flammable and volatile, and dry ice can cause frostbite (through contact with exposed skin) and suffocation (due to the large volume of carbon dioxide generated when it sublimes).
Stability and functional correctness
As an overclocked component operates outside of the manufacturer's recommended operating conditions, it may function incorrectly, leading to system instability. Another risk is
A large-scale 2011 field study of hardware faults causing a system crash for consumer PCs and laptops showed a four to 20 times increase (depending on CPU manufacturer) in system crashes due to CPU failure for overclocked computers over an eight-month period.[15]
In general, overclockers claim that testing can ensure that an overclocked system is stable and functioning correctly. Although software tools are available for testing hardware stability, it is generally impossible for any private individual to thoroughly test the functionality of a processor.[16] Achieving good fault coverage requires immense engineering effort; even with all of the resources dedicated to validation by manufacturers, faulty components and even design faults are not always detected.
A particular "stress test" can verify only the functionality of the specific instruction sequence used in combination with the data and may not detect faults in those operations. For example, an arithmetic operation may produce the correct result but incorrect flags; if the flags are not checked, the error will go undetected.
To further complicate matters, in process technologies such as silicon on insulator (SOI), devices display hysteresis—a circuit's performance is affected by the events of the past, so without carefully targeted tests it is possible for a particular sequence of state changes to work at overclocked rates in one situation but not another even if the voltage and temperature are the same. Often, an overclocked system which passes stress tests experiences instabilities in other programs.[17]
In overclocking circles, "stress tests" or "torture tests" are used to check for correct operation of a component. These workloads are selected as they put a very high load on the component of interest (e.g. a graphically intensive application for testing video cards, or different math-intensive applications for testing general CPUs). Popular stress tests include
Factors allowing overclocking
Overclockability arises in part due to the economics of the manufacturing processes of CPUs and other components. In many cases components are manufactured by the same process, and tested after manufacture to determine their actual maximum ratings. Components are then marked with a rating chosen by the market needs of the semiconductor manufacturer. If manufacturing yield is high, more higher-rated components than required may be produced, and the manufacturer may mark and sell higher-performing components as lower-rated for marketing reasons. In some cases, the true maximum rating of the component may exceed even the highest rated component sold. Many devices sold with a lower rating may behave in all ways as higher-rated ones, while in the worst case operation at the higher rating may be more problematical.
Notably, higher clocks must always mean greater waste heat generation, as semiconductors set to high must dump to ground more often. In some cases, this means that the chief drawback of the overclocked part is far more heat dissipated than the maximums published by the manufacturer. Pentium architect Bob Colwell calls overclocking an "uncontrolled experiment in better-than-worst-case system operation".[18]
Measuring effects of overclocking
Benchmarks are used to evaluate performance, and they can become a kind of "sport" in which users compete for the highest scores. As discussed above, stability and functional correctness may be compromised when overclocking, and meaningful benchmark results depend on the correct execution of the benchmark. Because of this, benchmark scores may be qualified with stability and correctness notes (e.g. an overclocker may report a score, noting that the benchmark only runs to completion 1 in 5 times, or that signs of incorrect execution such as display corruption are visible while running the benchmark). A widely used test of stability is Prime95, which has built-in error checking that fails if the computer is unstable.
Using only the benchmark scores, it may be difficult to judge the difference overclocking makes to the overall performance of a computer. For example, some benchmarks test only one aspect of the system, such as memory
Manufacturer and vendor overclocking
Overclocking is sometimes offered as a legitimate service or feature for consumers, in which a manufacturer or retailer tests the overclocking capability of processors, memory, video cards, and other hardware products. Several video card manufactures now offer factory-overclocked versions of their graphics accelerators, complete with a warranty, usually at a price intermediate between that of the standard product and a non-overclocked product of higher performance.
It is speculated that manufacturers implement overclocking prevention mechanisms such as
Many motherboards are sold, and advertised, with extensive facilities for overclocking implemented in hardware and controlled by BIOS settings.[19]
CPU multiplier locking
CPU multiplier locking is the process of permanently setting a
Users usually unlock CPUs to allow overclocking, but sometimes to allow for
Increasing front-side bus or northbridge/PCI clocks can overclock locked CPUs, but this throws many system frequencies out of sync, since the RAM and PCI frequencies are modified as well.
One of the easiest ways to unlock older AMD Athlon XP CPUs was called the pin mod method, because it was possible to unlock the CPU without permanently modifying bridges. A user could simply put one wire (or some more for a new multiplier/Vcore) into the socket to unlock the CPU. More recently however, notably with Intel's Skylake architecture, Intel had a bug with the Skylake (6th gen Core) processors where the base clock could be increased past 102.7 MHz, however functionality of certain features would not work. Intel intended to block base clock (BCLK) overclocking of locked processors when designing the Skylake architecture to prevent consumers from purchasing cheaper components and overclocking to previously-unseen heights (since the CPU's BCLK was no longer tied to the PCI buses), however for LGA1151, the 6th generation "Skylake" processors were able to be overclocked past 102.7 MHz (which was the intended limit by Intel, and was later mandated through later BIOS updates).[original research?] All other unlocked processors from LGA1151 and v2 (including 7th, 8th, and 9th generation) and BGA1440 allow for BCLK overclocking (as long as the OEM allows it), while all other locked processors from 7th, 8th, and 9th gen were not able to go past 102.7 MHz. 10th gen however, could reach 103 MHz [20] on the BCLK.
Advantages
This section possibly contains original research. (December 2011) |
- Higher performance in games, en-/decoding, video editing and system tasks at no additional direct monetary expense, but with increased electrical consumption and thermal output.
- System optimization: Some systems have "bottlenecks", where small overclocking of one component can help realize the full potential of another component to a greater percentage than when just the limiting hardware itself is overclocked. For instance: many motherboards with AMD Athlon 64 processors limit the clock rate of four units of RAM to 333 MHz. However, the memory performance is computed by dividing the processor clock rate (which is a base number times a CPU multiplier, for instance 1.8 GHz is most likely 9×200 MHz) by a fixed integer such that, at a stock clock rate, the RAM would run at a clock rate near 333 MHz. Manipulating elements of how the processor clock rate is set (usually adjusting the multiplier), it is often possible to overclock the processor a small amount, around 5–10%, and gain a small increase in RAM clock rate and/or reduction in RAM latency timings.
- It can be cheaper to purchase a lower performance component and overclock it to the clock rate of a more expensive component.
- Extending the practical service life of old or obsolete equipment.
Disadvantages
General
This section possibly contains original research. (December 2011) |
- Higher clock rates and voltages increase power consumption, also increasing electricity cost and heat production. The additional heat increases the ambient air temperature within the system case, which may affect other components. The hot air blown out of the case heats the room it's in.
- Fan noise: High-performance fans running at maximum speed used for the required degree of cooling of an overclocked machine can be noisy, some producing 50 dB or more of noise. When maximum cooling is not required, in any equipment, fan speeds can be reduced below the maximum: fan noise has been found to be roughly proportional to the fifth power of fan speed; halving speed reduces noise by about 15 dB.[21] Fan noise can be reduced by design improvements, e.g. with aerodynamically optimized blades for smoother airflow, reducing noise to around 20 dB at approximately 1 metre[citation needed] or larger fans rotating more slowly, which produce less noise than smaller, faster fans with the same airflow. Acoustical insulation inside the case e.g. acoustic foam can reduce noise. Additional cooling methods which do not use fans can be used, such as liquid and phase-change cooling.
- An overclocked computer may become unreliable. For example: Microsoft Windows may appear to work with no problems, but when it is re-installed or upgraded, error messages may be received such as a "file copy error" during Windows Setup.[22] Because installing Windows is very memory-intensive, decoding errors may occur when files are extracted from the Windows XP CD-ROM
- The lifespan of semiconductor components may be reduced by increased voltages and heat.
- Warranties may be voided by overclocking.
Risks of overclocking
- Increasing the operation frequency of a component will usually increase its thermal output in a linear fashion, while an increase in voltage usually causes thermal power to increase quadratically.[23] Excessive voltages or improper cooling may cause chip temperatures to rise to dangerous levels, causing the chip to be damaged or destroyed.
- Exotic cooling methods used to facilitate overclocking such as water cooling are more likely to cause damage if they malfunction. Sub-ambient cooling methods such as phase-change cooling or liquid nitrogen will cause water condensation, which will cause electrical damage unless controlled; some methods include using kneaded erasers or shop towels to catch the condensation.
Limitations
Overclocking components can only be of noticeable benefit if the component is on the critical path for a process, if it is a bottleneck. If disk access or the speed of an Internet connection limit the speed of a process, a 20% increase in processor speed is unlikely to be noticed, however there are some scenarios where increasing the clock speed of a processor actually allows an SSD to be read and written to faster. Overclocking a CPU will not noticeably benefit a game when a graphics card's performance is the "bottleneck" of the game.
Graphics cards
Graphics cards can also be overclocked. There are
Some overclockers apply a potentiometer to the graphics card to manually adjust the voltage (which usually invalidates the warranty). This allows for finer adjustments, as overclocking software for graphics cards can only go so far. Excessive voltage increases may damage or destroy components on the graphics card or the entire graphics card itself (practically speaking).
Flashing
Alternatives
Flashing and unlocking can be used to improve the performance of a video card, without technically overclocking (but is much riskier than overclocking just through software).
Flashing refers to using the
Some cards have abilities not directly connected with overclocking. For example, Nvidia's GeForce 6600GT (AGP flavor) has a temperature monitor used internally by the card, invisible to the user if standard firmware is used. Modifying the firmware can display a 'Temperature' tab.
Unlocking refers to enabling extra
See also
- Clock rate
- CPU-Z
- Double boot
- Dynamic voltage scaling
- POWER8 on-chip controller(OCC)
- Serial presence detect (SPD)
- Super PI
- Underclocking
- UNIVAC I Overdrive, 1952 unofficial modification
References
- ^ Victoria Zhislina (February 19, 2014). "Why has CPU frequency ceased to grow?". Intel. Archived from the original on June 21, 2017. Retrieved August 2, 2017.
- ^ "LIMITED WARRANTY" (PDF).
- ISBN 978-1-886411-76-0.
- ^ ISBN 978-1-886411-76-0.
- ^ ISBN 978-1-886411-76-0.
- ^ Stokes, Jon (June 22, 2006). "IBM's 500GHz processor? Not so fast…". Ars Technica. Archived from the original on October 20, 2017. Retrieved June 14, 2017.
- ^ Toon, John (June 20, 2006). "Georgia Tech/IBM Announce New Chip Speed Record". Georgia Institute of Technology. Archived from the original on July 1, 2010. Retrieved February 2, 2009.
- ^ "Intel Core i9 13900K Breaks the CPU Frequency World Record". Archived from the original on March 2, 2018. Retrieved December 9, 2022.
- ^ "Extreme-Temperature Electronics: Tutorial – Part 3". 2003. Archived from the original on March 6, 2012. Retrieved November 4, 2007.
- ^ Wes Fenlon (June 9, 2017). "Overclocking a CPU to 7 GHz with the science of liquid nitrogen". PC Gamer. Retrieved November 12, 2023.
- ^ "Overclocking to 7GHz takes more than just liquid nitrogen". Engadget. August 8, 2019. Retrieved November 12, 2023.
- ^ ISBN 978-1-886411-76-0.
- ^ "overclocking with dry ice!". TechPowerUp Forums. August 13, 2009. Archived from the original on December 7, 2019. Retrieved January 7, 2020.
- ^ Cooling baths – ChemWiki Archived 2012-08-28 at the Wayback Machine. Chemwiki.ucdavis.edu. Retrieved on 2013-06-17.
- ^ Cycles, cells and platters: an empirical analysis of hardware failures on a million consumer PCs (PDF). Proceedings of the sixth conference on Computer systems (EuroSys '11). 2011. pp. 343–356. Archived (PDF) from the original on November 14, 2012. Retrieved December 5, 2012.
- )
- ^ Chen, Raymond (April 12, 2005). "The Old New Thing: There's an awful lot of overclocking out there". Archived from the original on March 8, 2007. Retrieved March 17, 2007.
- S2CID 21582410.
- ^ "||ASUS Global". ASUS Global. Archived from the original on May 10, 2021. Retrieved May 10, 2021.
- ^ "Intel Core i5-10400F Review – Six Cores with HT for Under $200". TechPowerUp. May 28, 2020. Archived from the original on December 15, 2021. Retrieved December 15, 2021.
- ^ "UK Health and Safety Executive: Top 10 noise control techniques" (PDF). Archived (PDF) from the original on November 26, 2019. Retrieved December 30, 2011.
- ^ "Article ID: 310064 – Last Review: May 7, 2007 – Revision: 6.2 How to troubleshoot problems during installation when you upgrade from Windows 98 or Windows Millennium Edition to Windows XP". Archived from the original on May 15, 2009. Retrieved September 4, 2008.
- ISBN 978-1-119-78800-3.
- ^ "Alt+Esc | GTX 780 Overclocking Guide". Archived from the original on June 24, 2013. Retrieved June 18, 2013.
- Notes
- S2CID 21582410.
External links
- Media related to Overclocking at Wikimedia Commons
- OverClocked inside
- How to Overclock a PC, WikiHow
- Overclocking guide for the Apple iMac G4 main logic board
Overclocking and benchmark databases
- OC Database of all PC hardware for the past decade (applications, modifications and more)
- HWBOT: Worldwide Overclocking League – Overclocking competition and data
- Comprehensive CPU OC Database
- Segunda Convencion Nacional de OC: Overclocking Extremo by Imperio Gamer
- Tool for overclock