Overclocking
The trade-offs are an increase in power consumption (heat), fan noise (cooling), and shortened lifespan for the targeted components.
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 data corruption (incorrectly calculated results, or worse writing to storage incorrectly) or the system failing only during certain specific tasks (general usage such as internet browsing and word processing appear fine, but any application wanting advanced graphics crashes the system.
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.
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.
The usefulness of underclocking (again like overclocking) is determined by what processor offerings, prices, and availability are at the specific time of the build.
However, the practice is embraced more by enthusiasts than professional users, as overclocking carries a risk of reduced reliability, accuracy and damage to data and equipment.
Additionally, most manufacturer warranties and service agreements do not cover overclocked components nor any incidental damages caused by their use.
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.
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.
In addition, some digital circuits slow down at high temperatures due to changes in MOSFET device characteristics.
Thermoelectric cooling devices which actually refrigerate using the Peltier effect can help with high thermal design power (TDP) processors made by Intel and AMD in the early twenty-first century.
[9] These extreme methods are generally impractical in the long term, as they require refilling reservoirs of vaporizing coolant, and condensation can form on chilled components.
[13] Amateur overclocking enthusiasts have used a mixture of dry ice and a solvent with a low freezing point, such as acetone or isopropyl alcohol.
Such failures might never be correctly diagnosed and may instead be incorrectly attributed to software bugs in applications, device drivers, or the operating system.
Overclocked use may permanently damage components enough to cause them to misbehave (even under normal operating conditions) without becoming totally unusable.
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.
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.
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.
Popular stress tests include Prime95, Superpi, OCCT, AIDA64, Linpack (via the LinX and IntelBurnTest GUIs), SiSoftware Sandra, BOINC, Intel Thermal Analysis Tool and Memtest86.
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".
Many motherboards are sold, and advertised, with extensive facilities for overclocking implemented in hardware and controlled by BIOS settings.
AMD ships unlocked CPUs with their Opteron, FX, All Ryzen desktop chips (except 3D variants) and Black Series line-up, while Intel uses the monikers of "Extreme Edition" and "K-Series."
Contrary to popular belief, the "pin mod" method which claims to unlock older AMD Athlon XP CPUs does not work.
Similar to dynamic adjustments critical in network management for handling data flow and preventing bottlenecks, overclocking computer hardware requires ongoing monitoring and adaptations to maintain system stability and performance.
[25] It is sometimes possible to see that a graphics card is being pushed beyond its limits before any permanent damage is done by observing on-screen artifacts or unexpected system crashes.
Some overclockers apply a potentiometer to the graphics card to manually adjust the voltage (which usually invalidates the warranty).
GPUs found to be fully functional can be unlocked successfully, although it is not possible to be sure that there are undiscovered faults; in the worst case the card may become permanently unusable.
