Cooling s are often made of
copper. While stock cooling systems are commonly designed for heat produced during non-overclocked use, they may not be adequate for overclocked parts. These may include the use of additional and more powerful
fans, larger and more efficient
heat sinks,
heat pipes, or the use of
water cooling.
Heat sinks Heat sinks are passive
heat exchangers designed to take away excessive heat generated by the device it is in physical contact with. They are commonly made with
copper or
aluminum, with copper having higher
thermal conductivity, and aluminum being less efficient but also cheaper.
Heat pipes can be used to improve conductivity. Many heatsinks combine two or more materials to achieve a balance between performance and cost. such as record-setting attempts or one-off experiments rather than cooling an everyday system. In June 2006,
IBM and
Georgia Institute of Technology jointly announced a new record in silicon-based chip
clock rate (the rate a transistor can be switched at, not the CPU clock rate) above 500 GHz, which was done by cooling the chip to using liquid helium. The current CPU frequency world record is 9,130.33 MHz, achieved in August 2025 with an Intel
Core i9-14900KF. 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. so using extremely cold coolants may cause devices to fail.
Blowtorch is used to temporarily raise temperature to issues of over-cooling when not desirable. Submersion cooling, used by the
Cray-2 supercomputer, involves sinking a part of computer system directly into a chilled liquid that is thermally conductive but has low
electrical conductivity. The advantage of this technique is that no condensation can form on components. Amateur overclocking enthusiasts have used a mixture of
dry ice and a solvent with a low freezing point, such as
acetone or
isopropyl alcohol. This
cooling bath, often used in laboratories, achieves a temperature of .
Stability and reliability As an overclocked component operates outside of the manufacturer's recommended operating conditions, it may function incorrectly, leading to system instability. Another risk is
silent data corruption by undetected errors. 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. 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. Some semiconductor manufacturing techniques, like the
silicon on insulator (SOI), produce devices with
hysteresis behavior. These 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. Such a system may pass stress tests yet experiences instabilities in other programs.
Factors impacting overclocking potential 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". == Manufacturer and vendor ==