Enthusiasts have exceeded the limits of silicon as long as there are microprocessors. Early overclocking efforts included soldering and replacing quartz clock oscillators, but this practice quickly developed into a change in system bus speed via DIP switches and jumpers on the motherboard.
Internal clock multipliers were introduced, but it wasn't long before they were locked out as an unscrupulous seller removed official frequency ratings and attached their own faster markers. System buses and dividers became the key for most, while the ultra enthusiast would physically change the electrical specifications through hard modding.
The current landscape stems from the emergence of internal clock multipliers. System bus speeds have been increasingly regulated to maintain system stability, which has again balanced the competitive environment for competitive overclocking.
These are just a few of the key processors that are revered for their overclocking performance. Continue reading!
Note: This function was originally published on December 15th, 2014. We revised and bumped it because overclocking the CPU is as cool today as it has been since the i286 days. Part of our annual # ThrowbackThursday initiative.
Intel Pentium MMX 166
Release date: January 8, 1997
Camp cycle: 166 MHz
Overclocked: 207-266 MHz (~ 54%)
The Pentium MMX arrived amidst the shadows of the retailer, and vendors of x86 processors responded by blocking multiplier caps. Therefore, many MMXs were dependent on an increase in the bus frequency when overclocking. Unlocked MMX processors offered more options for overclockers, and the unlocked MXX 233 was the top bid, although its price of $ 594 was unaffordable for many.
At $ 407, the MMX 166 was a better value, and in combination with a solid 430TX-based motherboard with an out-of-the-box bus speed of 75 MHz, 225 or 266 MHz (3 or 3.5 Multi) was within range. To crack 200 MHz, MMX 166 with a locked multiplier would have to use the 83 MHz jumper setting, if available (2.5 * 83 for 207 MHz), although stability and heat build-up were far more problematic at this bus speed, as was the procurement of Quality EDO / SDRAM-RAM required to run at this frequency.
Release date: March 1992
Camp cycle: 40 MHz and 50 MHz
Overclocked: 66 MHz (~ 65%)
The P24 DX2 486 processors introduced the CPU clock multiplier and doubled the system bus speed, while the system bus frequency itself could be configured using motherboard jumpers or DIP switches. Initially with 20, 25, and 33 MHz options (later expanded to include 40 and 50 MHz models), users had a way to overclock without having to solder and replace the clock crystal oscillator.
Alternatively, you can get the performance of a DX2-66 for $ 799 by buying the cheaper 486DX2-40 for $ 400 and increasing the standard bus speed from 20 MHz to 33 MHz.
Stability and VLB slot problems at bus speeds above 33 MHz caused the overclocking margin to decrease as the base clock increased – to the extent that many Intel DX2-66 would not overclock at all and the few that did, often to 80 MHz (2nd x) was limited to 40 MHz).
Intel Celeron 300A
Release date: August 24, 1998
Camp cycle: 300 MHz
Overclocked: 375 – 504 MHz (~ 55%)
Think legendary. The Celeron 300A was instrumental in ensuring that overclocking the mainstream processor was brought back to life by the ease with which this could be achieved. 50% overclocking to 450 MHz was as easy as changing the bus speed from nominal 66 MHz to 100 MHz. Although some 83.3 MHz boards limited the OC to 375 MHz, motherboards that support 103 MHz FSB could deliver 464 MHz.
A better chip with a voltage rise could run at the FSB setting of 112 MHz to produce 504 MHz. Remarkably, the 300A could generally reach 450 MHz above the nominal 2.0 volts without additional voltage requirements. The chip's performance was also supported by an on-die L2 cache, which, at $ 149, was particularly accessible to system manufacturers.
AMD Athlon 700 (Thunderbird) / Duron 600 (Spitfire)
Release date: July 5, 2000 (Athlon 700) / June 19, 2000 (Duron 600)
Camp cycle: 700 MHz / 600 MHz
Overclocked: 770 – 900 MHz (~ 12%) / 800 – 1000 MHz (~ 59%)
AMD's Thunderbird Pencil Mod was an overclocker's dream. AMD locked the voltage and multipliers on its K7 line to limit the fraudulent remark made by processors to higher specifications. Overclockers quickly realized that the circuit bridges built into the silicon package were the key to unlocking the performance.
Initially, a combination of bridges in blocks L3, L4 and L6 gave way to bridging L1 links to unlock the multiplier. Bridging L7 connections to change the core voltage was also an option, and the process could be as simple as using a soft pencil or a conductive silver pen.
Because AMD's EV6 system bus is sensitive to overclocking, multiplier overclocking gave results, with the Duron leading thanks to its lower base core voltage (1.5V vs. 1.7 / 1.75V), which resulted in a higher relative overhead the maximum permissible 1.85 V enabled.
For $ 112 and a little bit of time, the Duron 600 could easily approximate a processor's performance many times its price.
Intel Core 2 Quad Q6600 G0 revision
Release date: January 8, 2007 (B0 revision) / July 22, 2007 (G0 revision)
Camp cycle: 2.4 GHz
Overclocked: 3.4 – 3.6 GHz (~ 46%)
The Core 2 Quad Q6600 achieved an enviable record in terms of longevity and performance, and was de facto the first choice for overclockers who want an inexpensive quad-core CPU. After the processor's price dropped from $ 851 in January 2007, it quickly dropped to $ 530 in May, and further price realignment in July coincided with the introduction of the G0 revision. At $ 266, the price of the 2.4 GHz quad-core chip was identical to the new dual-core 3 GHz E6850, a frequency that could comfortably exceed the previous B3 revision Q6600.
The new G0 stepping offered slightly lower power consumption, which resulted in the same improvement in overclocking capability, which meant that many users could maintain 3.4 to 3.6 GHz fairly easily. The introduction of the affordable Intel P35 platform and the further price reduction of the Q6600 to $ 224 (April) and $ 183 (October) by 2008 provided the opportunity for solid 50% overclocking (9x multiplier x 400MHz) FSB for 3.6 GHz) on a moderate budget that remained very competitive long after the fade of many of its contemporaries.
Intel Pentium III 500E
Release date: October 25, 1999
Camp cycle: 500 MHz
Overclocked: 667 – 775 MHz (~ 50%)
The Coppermine Pentium III 500E and 550E's overclockability is based on conservative binning, a low 100 MHz front-side bus and the processor's built-in L2 cache. The affordable price tag ($ 239) and the ability to use older Slot 1 motherboards through Socket 370 Slot 1 adapters enabled premium performance with little effort.
The 500E can easily operate at 667 MHz by selecting the motherboard's 133 MHz FSB BIOS option or by insulating the A14 pin of the socket with tape or paint, while 750 MHz (150 FSB) and higher on better boards are possible and achieve a performance that corresponds to the 850 dollar Pentium III 800.
However, there were some limitations to overclocking, including the fact that motherboards had to support AGP and PCI clock dividers (1: 2 and 1: 4) to maintain the stability of the connected components and the fast PC133 RAM.
AMD Athlon XP-M 2500+ (Barton Mainstream 45W TDP)
Release date: March 12, 2003
Camp cycle: 1.87 GHz
Overclocked: 2.4 – 2.7 GHz (~ 32%)
In early 2004, the overclocking community became aware that the Barton mobile processors not only have low-voltage operation (1.45 V compared to the 1.65 V desktop), but also an unlocked clock multiplier. These factors often led to phenomenal overclocking latitude – something the desktop models lack.
When the chip's overclocking potential became known, the rush was so great that within a few weeks its price rose by over 30% compared to the MSRP of $ 75. With a solid nForce2 motherboard, decent cooling, and willingness to raise the voltage to 1.8 V and higher, an overclocking of 30 to 40% was often achievable. While the impressive Speedbump couldn't close the performance gap to the new Athlon 64s, the Athlon XP-M 2500+ didn't cost $ 200 to $ 400.
AMD Opteron 144/146 (K8 Venus)
Release date: August 2, 2005
Camp cycle: 1.8 GHz / 2.0 GHz
Overclocked: 2.5 – 3.0 GHz (~ 63%)
Using the same silicon as AMD's Athlon 64 processors in San Diego, the Socket 939 Opterons for $ 125 and $ 183 had a significant price advantage over the similarly equipped Athlon 64 3700+ at $ 329 and outperformed the $ 1,000 -Dollar FX-57 claim even better.
As with all locked up multiplier processors, the Opteron's ability was directly tied to the strength of the motherboard used. Conservative binning of the Opteron server chips in conjunction with a solid overclocking board, for example with the nForce4 chipset with HyperTransport frequencies close to (and above) 300MT / s, would lead to overclocking that rarely occurs with enterprise-class processors.
Since all Opteron models have roughly the same overclocking limit, the cheapest 144 sold out quickly in many markets.
Intel Core i7 2600K / Core i5 2500K
Release date: January 9, 2011
Camp cycle: 3.4 GHz (3.8 GHz Turbo) / 3.3 GHz (3.7 GHz Turbo)
Overclocked: 4.6 – 5.0 GHz (~ 49%)
When Intel announced an upper clock multiplier limit and an almost non-existent system bus overclocking for its upcoming Sandy Bridge-compatible Cougar Point chipsets, this was widely touted as the end of overclocking on Intel platforms. The truth turned out that the 2500K and 2600K were first-class overclockers that required minimal time and cooling for stable overwatches in the 30-50% range.
The popularity of the 2600K was so great that the submissions of this processor accounted for around 28% of all CPU results to HWBot in 2011 and exceeded those of the successor, the 3770K, in 2012. Low cost of $ 216 plus solid cooling results when paired With air or water, Intel's 2500K became the de facto standard by which all other consumer CPUs were measured.
Intel Core i7 920
Release date: November 17, 2008
Camp cycle: 2.67 GHz (2.93 GHz Turbo)
Overclocked: 3.5 – 4.0 GHz C0 revision, 3.8 – 4.2 GHz D0 revision (~ 58%)
The new Nehalem architecture and the X58 platform offered enough promise to convince many users of durable Core 2 LGA 775 systems. While the flagship i7 965 EE was $ 1,000 cheaper than the Core 2 QX9770 at $ 1,000, it was still of little value compared to the i7 920.
First C0 revision Bloomfield CPUs have earned a reputation for high voltage requirements above 3.6 GHz. The following D0 often had the ability to maintain the nominal 1.26V to 4GHz and an absolute overclocking limit of almost 4.5GHz for those who are trying to bring the voltage closer to 1.5V.
The popularity of the 920 was (and is) so great that it represents over a third of HWBot's overclocking contributions for 64 LGA 1366 processors.
Intel Pentium 4 1.6A / Celeron 2.0 (Northwood)
Release date: January 7, 2002 (Pentium 4) / September 18, 2002 (Celeron 2.0)
Camp cycle: 1.6 GHz / 2.0 GHz
Overclocked: 2.4 – 2.8 GHz (~ 48%) / 2.66 – 3 GHz (~ 46%)
The arrival of the Northwood core was a welcome sight after the disappointing Williamette, the tension and heat of which suppressed serious overclocking for the mainstream. While the higher clocked P4s offered little or no value compared to the Athlon XP, the 1.6A at $ 125 turned a performance deficit into a gain with its low base FSB of 100 MHz, which was easy at a clock speed of 2.4 GHz could be increased to 150.
The overclocking of the Celeron was even higher thanks to a 20-fold multiplier, although the performance was severely limited by the meager 128 KB L2 cache. Those striving for higher overclocking would have to shift the core voltage over 1.6 V either via the BIOS settings or the wire mod (connecting the CPU pins to increase the Vcore limits), the latter largely for the phenomena of SNDS (Sudden Northwood Death Syndrome), better known as electromigration.
This factor and the 1.6A cannibalization of Intel's own more expensive models are seen as a motivation for the company to stop selling the 1.6A less than six months after its launch in January 2002.
Intel Xeon LV 1.6 D1 Revision (Prestonia)
Release date: September 2003
Camp cycle: 1.6 GHz
Overclocked: 2.6 – 3.2 GHz (~ 63%)
Overclocking is most commonly associated with game systems, but two-processor overclocking has had a solid following for over a decade. Long before the Intel QX9775 and Skulltrail board became the buzzword for performance overruns, many enthusiasts were looking for the budget Xeon LV 1.6.
The Prestonia core was basically the Pentium 4 Northwood with SMP (Symmetric Multiprocessing) and HyperThreading as standard functions. With the 1.6 GHz Xeon under $ 200, which consumes economical 1.274 V, overclockers were generally unable to use the voltage headroom, since most boards were voltage-blocked. Simply raising the FSB would result in 2.6 GHz net.
For the adventurous, three hard mods could achieve 100% overclocking (or more!): The U-Wire mod, which bridged two (1.5 V) or three (1.6 V) sets of socket pins, the BSEL mod to isolate or break the CPU pins and raise the FSB limit to 200 MHz and the vDIMM mod to increase the RAM voltage.
Those willing to push the boundaries of technology could be rewarded with a 3.2 GHz dual-processor king for around $ 700 (CPUs, cooler, board, and RAM).
AMD Athlon XP 1700+ (whole blood B)
Release date: June 10, 2002
Camp cycle: 1.46 GHz
Overclocked: 2.2-2.5 GHz (~ 44%)
The original whole blood A was little more than a shrink of the previous palomino and somewhat disappointing as an end product. The introduction of AMD's Thoroughbred-B in June 2002 was better aligned with the 130nm process and resulted in higher core frequencies as well as higher efficiency, since the B revision showed remarkable overclocking ability with minimal voltage increase.
When used in conjunction with a strong nForce2 chipset motherboard, the $ 60 XP 1700+ at its standard voltage was able to achieve a core speed of nearly 2 GHz. With an nF2 card that could push the system bus beyond 200 MHz, it was possible to maintain a 40% overclocking with a modest 1.7 V, the performance of the AMD flagship Athlon XP 2800+ worth $ 397 surpass and notify Intel's Pentium 4.
Intel Pentium D 820 / D 805
Release date: May 26, 2005 (D 820) / December 2005 (D 805)
Camp cycle: 2.8 GHz / 2.66 GHz
Overclocked: 3.5 – 4.2 GHz (~ 26%)
The Pentium D 820 was an anomaly with two single cores on an MCM package that was $ 241 a lot cheaper than the cheapest dual-core AMD Athlon 64 X2 and even the single-core Athlon 64 3500+ at $ 30 -Bid undercut. The Pentium D 820 offered modest performance that in no way challenged the Athlon Dual, but considerable overclocking scope with reasonable tension and a good air or water cooling system.
The arrival of Intel's $ 129 D 805 made the hot Netburst processor a budget overclocker. A reduction in the nominal system bus speed from 200 MHz to 133 was compensated for by the 20-fold clock multiplier of the D 805, which did not lead to a reduction in the overclocking fun. For those with modest means, a D 805 paired with a solid 945P card and value-oriented RAM was the value proposition that was the province of a processor-dictated build of $ 500.
Intel Pentium Dual Core E2140 / E2160
Release date: June 3, 2007
Camp cycle: 1.6 GHz (E2140) / 1.8 GHz (E2160)
Overclocked: 2.7 – 3.2 GHz (~ 89%) / 2.9 – 3.5 GHz (~ 92%)
Intel's E2000 series effectively signaled the end of both the last surviving NetBurst Pentium D and AMD's dominance on the budget market. Intel would halve the E4000 series L2 cache and further improve performance with a 200 MHz system bus (800 FSB). What Intel didn't do was remove the Conroe processor's ability to overclock.
You could achieve 50% overclocking with standard voltages and the standard cooler by simply increasing the bus speed to 300 MHz either on an affordable Intel-based P965 / P35 board or one with an Nvidia 650i SLI chipset that, thanks to options, offers greater options with cheaper RAM enables its non-dependency on memory dividers.
An aftermarket air cooler, voltage adjustment, and some luck with the silicon lottery could see the processors at or near 100% overclocking, delivering performance at the level of the E6700 at a fraction of the cost.
AMD Phenom II X2 550 Black Edition (Callisto) / X4 955 Black Edition (Deneb)
Release date: June 1, 2009 (X2 550 BE) / April 23, 2009 (X4 955 BE)
Camp cycle: 3.1 GHz / 3.2 GHz
Overclocked: 3.7 – 3.9 GHz (~ 22%)
With the release of AMD's revised K10.5 architecture in the first months of 2009, the company's strong value proposition was revived. With the advent of the Black Edition processors, the unlocked multiplier was also added to make overclocking easier.
While the possible clock rate increases were not excessive in historical comparison, they were accompanied by actual performance increases that comfortably lifted them out of the Core 2 quad shadow. At $ 100, the 550 Black Edition was superlative when the two deactivated cores could be unlocked (unlocking the fourth core would be an important selling point for the X3 720 BE), while the 245 955 BE's absolute performance did only the more expensive X58 platform from Intel surpassed its potential.
Intel Core 2 Duo E6600 (Conroe)
Release date: July 27, 2006
Stock core clock: 2.4 GHz
Overclocked: 3.0 – 4.0 GHz (~ 45%)
When Intel's Conroe architecture arrived in July 2006, the main focus was on the unlocked multiplier X6800, but it was the cheapest fully activated chip (4MB L2 cache) that stole the show. For $ 316, the chip was a full $ 200 less than the next performance upgrade (the E6700) and was already delivering results that rivaled AMD's top Athlon 64.
With standard cooling and standard voltages, you can generally rely on the E6600 to reach 2.7 to 3 GHz. If you had an aftermarket cooler, the stability of the motherboard was often the limiting factor as the system bus speeds went over 400 MHz and rose towards 450. The overclocking potential was so great that the Athlon 64 FX-62, valued at 999 x 6800 and $ 799, looked positively ridiculous compared to the price and performance of the E6600.
Intel Core 2 Duo E8400 E0 Revision (Wolfdale-6M)
Release date : January 7, 2008 (C0 revision) / July 18, 2008 (E0 revision)
Camp cycle: 3.0 GHz
Overclocked: 4.0 – 4.5 GHz (~ 41%)
The first C0 revision in January 2008, the Wolfdale-based E8400, immediately established itself as an affordable performance overclocking processor. Five months later, the E0 revision brought with it a much more refined voltage requirement. While some C0-Step E8400s were powerful at the 4 GHz level, the new version was often able to achieve the same frequency with the voltage, the settings and the cooler in stock.
At the time of the arrival of the E0, the price of the OEM package with a range of very powerful P45 and X48 cards capable of maintaining bus speeds near 500 MHz (2000 MHz FSB) had dropped to $ 149. The continued stability of these 4 + GHz systems many years later is proof of the quality of both the architecture and the chipsets.
Would you like to learn more about CPUs?
Check out our series on the history of the microprocessor
Or the best CPUs you can currently buy
For easier reading …
Top 10 tech pranks
Or tips and tricks for Power User PCs that you should know