Fanatics have been pushing the bounds of silicon for so long as microprocessors have existed. Early overclocking endeavors concerned soldering and changing crystal clock oscillators, however that apply shortly advanced into adjusting system bus speeds utilizing motherboard DIP switches and jumpers.
Inside clock multipliers have been ultimately launched, but it surely did not take lengthy for these to be locked down, as unscrupulous sellers started eradicating official frequency scores and rebranding chips with their very own sooner markings. System buses and dividers turned the first tuning instruments for many customers, whereas ultra-enthusiasts went additional – bodily altering electrical specs by means of onerous modding.
Finally, unlocked multipliers made a comeback, ushering in an period outlined by BIOS-level overclocking and more and more refined software program tuning instruments. Over the previous decade, nonetheless, conventional overclocking has grow to be extra constrained. Improved manufacturing unit binning, aggressive turbo enhance algorithms, and thermal ceilings imply that trendy CPUs typically function close to their peak potential proper out of the field.
With system bus speeds now tightly managed to keep up platform stability, most trendy overclocking is finished by means of BIOS menus or manufacturer-provided utilities. The problem has shifted from {hardware} hacking to managing thermals, navigating firmware quirks, and successful the silicon lottery – however the spirit of overclocking stays alive, pushed by these nonetheless chasing free efficiency on the edge of what is doable.
This is a consultant pattern of the landmark processors revered for his or her overclocking prowess. Learn on!
Be aware: This TechSpot characteristic was initially printed in December 2014. We proceed to replace and resurface it periodically as a result of CPU overclocking stays nearly as cool in the present day because it was again within the 486DX days.
Intel Pentium MMX 166
The Pentium MMX arrived amid the peak of retailer shadiness and x86 processor distributors responded by locking higher limits for multipliers. As such, many MMXs relied on bus frequency will increase for overclocking. Unlocked MMX processors provided extra choices for overclockers and the unlocked MXX 233 reigned supreme, although its $594 value was prohibitive for a lot of.
At $407, the MMX 166 was a greater worth, and when paired with a stable 430TX-based motherboard that had a bus pace of 75MHz out of the field, 225 or 266MHz (3 or 3.5 multi) was inside attain. To crack 200MHz, MMX 166s with a locked multiplier would wish to make use of the 83MHz jumper setting if obtainable (2.5 * 83 for 207MHz), though stability and warmth build-up at this bus pace have been much more problematic, as was the sourcing of high quality EDO/SDRAM RAM required to run at this frequency.
Intel 486DX2-40
The P24 DX2 486 processors launched the CPU clock multiplier, doubling the system bus pace, whereas the system bus frequency itself was configurable by way of motherboard jumpers or DIP switches. Initially together with 20, 25 and 33MHz choices (later augmented by 40 and 50MHz fashions), customers had a path to overclocking that did not require soldering and changing the clock crystal oscillator.
Alternatively, you may get the efficiency of a $799 DX2-66 by buying the extra modestly priced 486DX2-40 for $400 and elevating its default bus pace from 20MHz to 33MHz.
Stability and VLB slot points at bus speeds over 33MHz meant that overclocking headroom decreased as the bottom clock rose – to the extent that many Intel DX2-66s would not overclock in any respect and the few that did have been typically restricted to 80MHz (2 x 40MHz).
AMD K6-2 300 / 350
Although the K6-2 struggled towards Intel’s Pentium II and III in uncooked efficiency, it was extraordinarily standard amongst fanatics seeking to construct reasonably priced PCs. The addition of 3DNow! directions gave it a slight edge in multimedia and gaming workloads that might leverage SIMD.
Fanatics with Tremendous Socket 7 motherboards typically pushed the 300 and 350MHz fashions to 400MHz and past. Whereas not revolutionary when it comes to clock headroom, the K6-2’s broad availability, low price, and tweakability made it a memorable a part of the overclocking tradition of the late Nineteen Nineties.
Intel Celeron 300A
Suppose legendary. The Celeron 300A was largely liable for reigniting mainstream processor overclocking within the late 90’s by means of the convenience that it could possibly be achieved. A 50% overclock to 450MHz was so simple as altering the bus pace from its nominal 66MHz to 100MHz. Though some boards topped out at 83.3MHz limiting the OC to 375MHz, motherboards that supported 103MHz FSB might yield 464MHz.
A greater chip with a voltage bump might run on the 112MHz FSB setting to provide 504MHz. Remarkably, the 300A might typically attain 450MHz with none further voltage requirement over the nominal 2.0 volts. The chip’s efficiency was additionally aided by having an on-die L2 cache and with a value of $149 it was significantly accessible to system builders.
Additionally value mentioning, Intel’s Celeron 366 (Mendocino) famously hit 550MHz with an excellent cooler and a 100MHz FSB. Proper after the 300A, it was a part of the golden age of overclocking on a budget.
AMD Athlon 700 (Thunderbird) / Duron 600 (Spitfire)
AMD’s Thunderbird pencil mod was an overclocker’s dream. AMD locked the voltage and multipliers of its K7 line in an effort to curtail the fraudulent remarking of processors to greater specs. Overclockers shortly realized that the circuit bridges constructed into the silicon package deal held the important thing to unlocking efficiency.
Initially, a mix of connecting bridges within the L3, L4, and L6 blocks gave option to the bridging of L1 connections to unlock the multiplier. Bridging L7 connections to change core voltage was additionally an choice and the method could possibly be as simple as utilizing a gentle lead pencil or conductive silver pen.
With AMD’s EV6 system bus being delicate to overclocking, multiplier overclocking offered outcomes with the Duron main the way in which because of its decrease base core voltage (1.5v versus 1.7 /1.75v), which enabled greater relative overhead to the utmost 1.85v allowed.
For $112 and a bit of time, the Duron 600 simply approximated the efficiency of a processor many instances its value.
Intel Core 2 Quad Q6600
The Core 2 Quad Q6600 achieved an enviable report of longevity and efficiency worth, turning into the de-facto alternative for overclockers who needed a price range quad-core CPU. As soon as the processor dropped in value from the preliminary $851 in January 2007, it shortly fell to $530 in Might and additional pricing realignment in July coincided with the arrival of the G0 revision. At $266, the two.4GHz quad-core chip was priced identically to the brand new dual-core 3GHz E6850, a frequency that the sooner B3 revision Q6600 might comfortably eclipse.
The brand new G0 stepping provided barely decrease energy consumption, which translated into the identical enchancment in overclocking potential, leading to many customers having the ability to maintain 3.4 to three.6GHz pretty readily. The introduction of the reasonably priced Intel P35 platform and additional Q6600 value chopping by means of 2008 to $224 (April) and right down to $183 (October) offered the chance for stable overclocking within the 50% vary (9x multiplier x 400MHz FSB for 3.6GHz) on a average price range that remained very aggressive lengthy after lots of its contemporaries had light.
Intel Pentium III 500E
The Coppermine Pentium III 500E and 550E’s overclockability lie in conservative binning, a low 100MHz Entrance Facet Bus and the processor’s built-in L2 cache. Funds pricing ($239) and the potential of utilizing older Slot 1 motherboards by way of Socket 370 to Slot 1 adapters enabled premium efficiency for a modest outlay.
The 500E might simply be run at 667MHz by choosing the motherboard’s 133MHz FSB BIOS choice or through the use of tape or lacquer to isolate the Slocket’s A14 pin, whereas 750MHz (150 FSB) and better have been doable on higher boards, producing efficiency equal to the $850 Pentium III 800.
Nevertheless, there have been some caveats to overclocking, together with that motherboards wanted to assist AGP and PCI clock dividers (1:2 and 1:4 respectively) to keep up stability for hooked up parts and quick PC133 RAM.
AMD Athlon XP-M 2500+ (Barton Mainstream 45W TDP)
In early 2004 it got here to the eye of the overclocking group that the cell Barton processors featured an unlocked clock multiplier along with being binned for low-voltage operation (1.45v in contrast with the desktop 1.65v). These components typically produced phenomenal overclocking headroom – one thing missing within the desktop fashions.
When the chip’s overclocking potential was publicized, such was the stampede that its value escalated over 30% from the $75 MSRP in a matter of weeks. With a stable nForce2 motherboard, first rate cooling and a willingness to push the voltage to 1.8v and better, a 30 to 40% overclock was typically attainable. Whereas the spectacular pace bump could not bridge the efficiency hole to the brand new Athlon 64s, the Athlon XP-M 2500+ did not price $200 to $400 both.
AMD Opteron 144 / 146 (K8 Venus)
That includes the identical silicon as AMD’s San Diego-based Athlon 64 processors, the $125 and $183 Socket 939 Opterons loved a big pricing benefit over the equally featured Athlon 64 3700+ at $329 and stacked up even higher towards the $1,000 FX-57.
Like all upwardly locked multiplier processors, the Opteron’s potential was tied on to the energy of the motherboard getting used. Conservative binning of the Opteron server chips allied with a stable overclocking board resembling these sporting the nForce4 chipset with HyperTransport frequencies approaching (and exceeding) 300MT/sec would result in overclocks seldom seen with enterprise-class processors.
With all of the Opteron fashions having roughly the identical overclock ceiling, the bottom priced 144 bought out shortly in lots of markets.
Intel Core i7 2600K / Core i5 2500K
When Intel introduced an higher clock multiplier restrict and nearly non-existent system bus overclocking for its upcoming Sandy Bridge appropriate Cougar Level chipsets, it was extensively touted as the top of overclocking on Intel platforms. The reality turned out to be that the 2500K and 2600K have been premier overclockers requiring minimal effort in time and cooling for steady overclocks within the 30 to 50% vary.
Such was the recognition of the 2600K that submissions from this processor accounted for round 28% of all CPU outcomes to HWBot in 2011 and would exceed these of its successor, the 3770K, in 2012. A low price of $216 plus stable cooling outcomes when paired with both air or water made Intel’s 2500K the de facto normal by which all different client CPUs have been judged.
Intel Core i7 920
The brand new Nehalem structure and X58 platform provided sufficient promise to coax many customers from long-lived Core 2 LGA 775 programs. Whereas the flagship i7 965 EE at $1,000 was cheaper than the Core 2 QX9770 by a 3rd, it nonetheless represented little in the way in which of worth in comparison with the i7 920.
Preliminary C0 revision Bloomfield CPUs earned a repute for prime voltage necessities previous 3.6GHz, the next D0 typically had the flexibility to keep up the nominal 1.26v as much as 4GHz and an absolute overclock ceiling approaching 4.5GHz for these tempted to show the voltage nearer to 1.5v.
Such was (and is) the 920’s reputation that it represents over a 3rd of HWBot’s overclocking submissions for 64 LGA 1366 processors.
Intel Pentium 4 1.6A / Celeron 2.0 (Northwood)
The arrival of the Northwood core was a welcomed sight after the disappointing Williamette, whose voltage and ensuing warmth stifled critical overclocking for the mainstream. Whereas the higher-clocked P4s provided little if any worth towards the Athlon XP, the 1.6A at $125 turned a efficiency deficit right into a win with its low base FSB of 100MHz which might simply be elevated to 150 for a 2.4GHz clock pace.
The Celeron’s overclock was greater nonetheless because of a 20x multiplier, though efficiency was closely constrained by the meager 128KB L2 cache. These searching for greater overclocks would wish to push the core voltage previous 1.6v both by means of BIOS settings or the wire mod (connecting CPU pins to lift Vcore limits), the latter being largely liable for the phenomena of S.N.D.S. (Sudden Northwood Dying Syndrome), extra generally referred to as electromigration.
This issue and the 1.6A cannibalizing Intel’s personal greater priced fashions are seen because the motivation for the corporate to stop gross sales of the 1.6A barely six months after its introduction in January 2002.
AMD FX-8350 (Vishera)
The FX-8350 was a polarizing chip. Primarily based on AMD’s Piledriver structure, it was marketed as an 8-core processor, although in actuality it had 4 integer modules with dual-core capabilities. Whereas its single-threaded efficiency lagged behind Intel’s choices, the FX-8350 turned an overclocking favourite as a result of its unlocked multiplier and unimaginable thermal headroom.
Many customers pushed it previous 5GHz with good aftermarket cooling, and it turned a cult basic within the fanatic scene, particularly in price range gaming rigs and benchmark competitions.
Intel Xeon LV 1.6 D1 (Prestonia)
Overclocking is most frequently related to gaming programs, however dual-processor overclocking has maintained a stable following for over a decade. Lengthy earlier than the QX9775 and Intel’s Skulltrail board turned the watchwords for efficiency extra, many fanatics sought the price range Xeon LV 1.6.
The Prestonia core was mainly the Pentium 4 Northwood with SMP (symmetric multiprocessing) and HyperThreading added as normal options. With the sub-$200 1.6GHz Xeon drawing a frugal 1.274v, overclockers typically could not benefit from voltage headroom as most boards have been voltage-locked. Nevertheless, merely elevating the FSB would internet 2.6GHz.
For the extra adventurous, three onerous mods might yield a 100% overclock (or extra!): the U-Wire mod which concerned bridging two (1.5v) or three (1.6v) units of socket pins, the BSEL mod to isolate or break CPU pins and lift the FSB restrict to 200MHz, and the vDIMM mod to lift RAM voltage.
These prepared to push the bounds of the know-how could possibly be rewarded with a 3.2GHz twin processor efficiency king for round $700 (CPUs, coolers, board, and RAM).
AMD Athlon XP 1700+ (Thoroughbred-B)
The preliminary Thoroughbred-A was little greater than a die shrink of the earlier Palomino and was considerably disappointing as a closing product. The June 2002 introduction of AMD’s Thoroughbred-B was extra tuned for the 130nm course of and resulted in greater core frequencies together with being extra environment friendly because the ‘B’ revision demonstrated a outstanding overclock potential with minimal if any voltage will increase.
Allied with a robust nForce2 chipset motherboard, the $60 XP 1700+ was absolutely able to close to 2GHz core pace at its default voltage. With an nF2 board able to pushing the system bus previous 200MHz, it was doable to maintain a 40% overclock with a modest 1.7v, eclipsing the efficiency of AMD’s $397 Athlon XP 2800+ flagship and placing Intel’s Pentium 4 on discover.
Intel Pentium D 820 / D 805
The Pentium D 820 was one thing of an anomaly with two single cores on an MCM package deal for less expensive than the most cost effective dual-core AMD Athlon 64 X2 at $241 and even undercut the only core Athlon 64 3500+ by $30. The Pentium D 820 provided modest efficiency by no means difficult the Athlon twin, however some appreciable overclocking headroom with even handed voltage and an excellent air or water-cooling system.
The arrival of Intel’s $129 D 805 additional endeared the recent Netburst processor to the price range overclocker. A discount in nominal system bus pace from 200MHz to 133 was offset by the D 805’s 20x clock multiplier, leading to no discount in overclocking enjoyable. For these of modest means, a D 805 paired with a stable 945P board and value-orientated RAM held the promise of efficiency that was the province of a $500 processor-dictated construct.
Intel Pentium Twin Core E2140 / E2160
Intel’s E2000 sequence successfully signaled the top of each the final surviving NetBurst Pentium D and AMD’s dominance within the price range market. Intel would halve the L2 cache of the E4000 sequence and additional hobble efficiency with a 200MHz (800 FSB) system bus. What Intel did not do was take away the Conroe processor’s potential to overclock.
You possibly can hit a 50% overclock with default voltages and the inventory cooler by merely elevating the bus pace to 300MHz on both an reasonably priced Intel-based P965/P35 board or one with an Nvidia 650i SLI chipset which allowed better choices with cheaper RAM because of its non-reliance on reminiscence dividers.
An aftermarket air cooler, voltage adjustment and a few luck within the silicon lottery might see the processors at or close to a 100% overclock, delivering efficiency across the degree of the E6700 for a fraction of the fee.
Intel Core i5 750 (Lynnfield)
The Core i5 750 was Intel’s first mainstream quad-core processor with out Hyper-Threading, based mostly on the Nehalem-derived Lynnfield structure. It featured an built-in reminiscence controller and a DMI hyperlink for PCIe immediately from the CPU, bettering latency and effectivity.
Although it lacked an unlocked multiplier, its base clock (BCLK) was extremely tweakable, permitting fanatics to succeed in practically 4GHz with good cooling. As the primary true successor to Core 2 Quad on the LGA1156 platform, it turned a gateway chip into the Nehalem period and remained viable for years with overclocking.
AMD Phenom II X2 550 Black Version (Callisto) / X4 955 Black Version (Deneb)
The discharge of AMD’s revised K10.5 structure throughout the early months of 2009 marked a resurgence of the corporate’s robust worth proposition. The emergence of the Black Version processors additionally added the welcome addition of the unlocked multiplier to facilitate overclocking.
Whereas the eventual clock pace will increase weren’t extreme by historic requirements, they did go hand in hand with precise efficiency beneficial properties which comfortably lifted them out of the Core 2 Quad shadow. At $100, the 550 Black Version represented a superlative worth if the 2 disabled cores could possibly be unlocked (the unlocking of the fourth core can be a significant promoting level for the X3 720 BE), whereas the outright efficiency of the $245 955 BE ensured that solely Intel’s costlier X58 platform exceeded its potential.
Intel Core 2 Duo E6600 (Conroe)
When Intel’s Conroe structure arrived in July 2006, many of the consideration was targeted on the unlocked multiplier X6800, but it surely was the most cost effective absolutely enabled (4MB L2 cache) chip that stole the present. For $316, the chip price a full $200 lower than the following step up in efficiency (the E6700) and already offered outcomes that rivaled AMD’s high Athlon 64s.
With inventory cooling and default voltages, you may typically depend on the E6600 to hit 2.7 to 3GHz. If you happen to had an aftermarket cooler, motherboard stability was typically the limiting issue as system bus speeds flew previous 400MHz and edged in the direction of 450. Such was the overclocking potential that the $999 X6800 and $799 Athlon 64 FX-62 regarded positively ludicrous when evaluating value and efficiency with the E6600.
Intel Core 2 Duo E8400 E0 (Wolfdale-6M)
The preliminary January 2008 C0 revision Wolfdale-based E8400 had instantly ensconced itself as an reasonably priced efficiency overclocking processor. 5 months later, the E0 revision introduced a a lot refined voltage requirement. Whereas some C0-step E8400s have been succesful performers on the 4GHz degree, most of the time, the identical frequency could possibly be achieved with inventory voltage, settings, and cooler with the brand new revision.
By the point the E0 arrived, pricing had fallen to $149 for the OEM package deal with a spread of very succesful P45 and X48 boards in a position to preserve bus speeds within the neighborhood of 500MHz (2000MHz FSB). The continued stability of those 4+GHz programs a few years later is a testomony to the standard of each the structure and the chipsets.
Intel Core i7 3930K (Sandy Bridge-E)
The Core i7 3930K was Intel’s reply to high-end fanatics and prosumers within the early 2010s. That includes 6 cores and 12 threads on the Sandy Bridge-E platform, the chip ran on the LGA 2011 socket and required the X79 chipset.
Because of its unlocked multiplier and improved thermals over earlier hex-core choices, the 3930K routinely achieved overclocks above 4.5GHz with enough cooling. Paired with quad-channel reminiscence and robust motherboard VRMs, it turned a go-to chip for energy customers, avid gamers, and video editors, sustaining relevance effectively into the Skylake period.
Picture supply: PCPer
Intel Core i7 4790K (Satan’s Canyon)
Satan’s Canyon was Intel’s response to criticisms of Haswell’s poor thermals. With improved thermal interface materials (TIM) and refined energy supply, the 4790K was the highest-clocked inventory CPU Intel had ever launched on the time.
Overclockers persistently reached between 4.7GHz and 5.0GHz on air or AIO water cooling setups. Its distinctive single-threaded efficiency and constant stability made it a mainstay in gaming builds for years, with many programs constructed on Z97 platforms persevering with to ship lengthy after newer generations had arrived.
AMD Ryzen 5 1600 AF
Initially considered a re-release of the unique Ryzen 5 1600, the 1600 AF turned out to be a hidden gem. Manufactured on the newer 12nm Zen+ course of fairly than the unique 14nm, the chip successfully carried out like a Ryzen 5 2600 whereas retaining the unique title and lower cost tag.
Because of improved thermal effectivity and higher reminiscence assist, overclockers routinely pushed it to just about 4.2GHz. The 1600 AF turned an unbeatable worth proposition in 2020, providing six cores and twelve threads at round $85 and dominating the price range fanatic scene.
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