How to overclock your CPU

For this edition of Press Start, we'll get you familiar with the basics of overclocking and explain what kind of equipment you'll need to get started.

by

Why overclock?

Overclocking the system processor is one of the easiest tweaks you can do to get more performance out of your PC. Motherboard manufacturers have steadily opened up more voltage and clock-speed options within the system BIOS to give ambitious overclockers the tools they need to get the most out of their CPUs. Processor manufacturers, desperate to capture the gaming market, have also relaxed their anti-overclocking stance, as we've recently seen in awkward lunges aimed at the PC gamer: the "unlocked" Athlon 64 FX and the Intel Extreme Edition processors.

The FX and Extreme Edition chips fill a need for extreme overclockers who are looking to create the fastest chip possible using any means necessary. But regular enthusiasts know that paying $1,000 for an unlocked chip violates the spirit of overclocking--the entire purpose of the act is to get an inexpensive processor running as fast as a ridiculously expensive one.

For this edition of Press Start, we'll get you familiar with the basics of overclocking and explain what kind of equipment you'll need to get started. This feature isn't a comprehensive guide, as there are entire Web sites devoted to the subject, but hopefully you'll learn enough to determine whether or not you'd like to give overclocking a try.

What you need

If you want to overclock effectively, you need a few choice components. You'll want to get a CPU that has lots of headroom, a large speed margin between its standard speed and the top speeds achieved by other processors that share the same basic microarchitecture design. You're also going to need a motherboard that gives you the necessary overclocking tools like CPU and northbridge voltage selection options. Then you might want to consider upgrading the CPU cooling, although that does add considerable expense and some CPUs have been known to be phenomenal overclockers using the stock fans and heatsinks.

The CPU model greatly affects what kind of overclock you can expect. Numerous Web sites and forums cover which processors are the most suitable for overclocking. For a good budget overclocking attempt, you want to stick to CPUs that cost less than $250. Sometimes, great bargains appear in the $150 range, but they don't come along too often. Among modern processors, the best bets for overclocking lie in the budget segments of Intel's new Core2 Duo and AMD's Athlon 64 X2 processors. Exact model numbers will vary as time goes on, but you usually want to go with the slower processor models since they're cheaper and provide more overclocking headroom.

Not all CPUs of the same model will overclock to the same levels. Some CPUs can run a little faster, while others can't. The more expensive processors have all been qualified to run at higher speeds, but the cheaper processors may have only graded out at lower speeds. When you buy a processor specifically for overclocking you're basically betting that the manufacturer's production quality is high enough that even the inexpensive chips can run at much faster speeds.

Pair up your CPU with memory suitable for the job. If you're going for a budget overclock, purchase only the speed you need. Low latency memory and high-speed memory cost a substantial amount and provide marginal gains in comparison to a large CPU overclock. If you're looking to squeeze out the most performance, regardless of budget, then premium memory is worth exploring. Buying faster memory "in preparation for the future" is pointless since you'll likely need a new a type of memory by the time you're ready to upgrade.

You will also need a motherboard that's willing to cooperate in the overclocking plan. Companies like Asus, DFI, MSI, Gigabyte, and Abit all manufacture motherboards specifically made for the tweaker. These motherboards feature extra options in the BIOS, more advanced cooling features, and better power-handling capabilities. Stay away from Intel brand boards and many name-brand pre-built systems if you plan on overclocking since they often don't have the BIOS settings that allow you to overclock the processor.

Extra cooling in the form of faster fans, better heat sinks, and water cooling (if you want to go exotic) all help to improve your chances of achieving a successful overclock. Some notable companies in the field of cooling include Thermaltake, Zalman, Alpha, and Thermalright among others, but lots of overclockers have had good success using the standard cooling units that come with the processor.

A good thermal paste, when correctly applied, is an absolute must-have especially if you're sticking with the stock heatsink and fan. There's no shortage of companies pedaling a cornucopia of metallic slimes: Arctic Silver, OCZ, Masscool, Antec, Kingwin, Cooler Master, and Artic Cooling. The key to unlocking the benefits of thermal compounds involves how you apply them. Make sure to place an even and very thin layer over the CPU. If you have too much paste on the CPU, the compound actually inhibits the transfer of heat to the heatsink.

Are you an experienced veteran with several processors under your belt? What CPU do you have and how high have you overclocked it?

Overclocking basics

Back in ancient times (1990), a computer's CPU frequency was essentially the entire computer's frequency. A computer running at 5MHz, or 30MHz, meant that just about every single component in the computer ran at that speed too. As processor technology improved, engineers realized that running the CPU at the same speed as the system might not be the best way to go about things. At that point, starting with Intel's 486 class of CPUs, multipliers were born. The Intel 486DX2 66MHz CPU ran at twice the speed of the front-side bus (33Mhz) and therefore had a multiplier setting of two. The CPU now ran twice as fast as everything else in the computer. Fast forward to modern day and it's common to see both AMD and Intel use multiplier settings of 15 and above.

The other component to the CPU's final speed is the front-side bus (FSB). The FSB refers to how fast the communication link between the CPU and chipset operates. Modern computers typically operate on a 133MHz, 200MHz, or 266MHz FSB. Although, you've probably seen numbers like 533MHz, 800MHz, 1000MHz, and 1066MHz thrown around, those figures are based off the original FSB. In Intel's case, the company uses a quad-pumped bus that allows the chipset to communicate four times per cycle (or Hz), which means that a quad-pumped 200MHz FSB effectively communicates like it's at 800MHz (4x200MHz). In AMD's case, the company actually stepped away from traditional FSB architecture, and adopted the HyperTransport bus, which has a default value of 200MHz. Using that figure, you then multiply the HyperTransport bus speed and the multiplier to arrive at the final CPU speed.

If you know how to multiply, then you can overclock. Most overclocking follows the following formula:

(Multiplier) x (FSB) = Final CPU speed

Depending on what kind of CPU you own, there are essentially two different methods to overclocking--multiplier overclocking and bus-speed overclocking.

How to overclock using the multiplier

Most people don't fall into this category because the powers that be (AMD and Intel) lock the multiplier on their processors. The only way you can get a factory-unlocked processor these days is to pay exorbitant amounts for AMD's FX and Intel's Extreme Edition line of CPUs.

Multiplier-unlocked CPUs allow you to change the multiplier at will. You can easily switch the 2.6GHz Athlon FX-60's default multiplier from 13 to 14, and have the CPU running at 2.8GHz in no time at all. The great benefit of a CPU with an unlocked multiplier means that you don't have to push the rest of your computer beyond its limits if you don't want to. You can put all the stress only on the CPU and leave the FSB untouched to keep the rest of the system operating within normal parameters.

Most overclocker-friendly motherboards will offer the option to change multiplier settings in the CPU section of the BIOS. However, most of us won't have the luxury of using the multiplier to overclock.

How to overclock using the FSB

If you can't adjust the CPU multiplier, the only way to increase the speed will be to jack up the FSB. When you overclock using the FSB, you're going to stress the CPU as well as just about every other component in the system, which mainly means that you'll need a quality motherboard. If you also want to overclock the memory subsystem, make sure to get premium RAM.

The trick to overclocking the FSB is to move up in small increments until you experience minor instabilities. Motherboards built for overclocking will allow you to edge up the speed in very small increments, and they'll also offer several voltage options to help maintain system stability.

Both types of overclocking can benefit from increased power levels. However, don't push the CPU voltage levels too high. More power inevitably leads to more heat, which directly translates to a reduced electronic life span. If you're trying to squeak out an extra 100MHz with a disproportionate amount of power, you're better off going with the slower speed and a lower voltage setting. You're not likely to notice the difference between 2.8GHz and 2.9GHz, but you will notice when your computer becomes a premature doorstop.

Testing and maintenance

Be sure to thoroughly test your system out before you call it a day. Run tests like 3DMark06 and Prime95 to ensure that your system runs properly. Don't be satisfied with minor, one-off testing either. Run your tests in continuous loops for at least a few hours, if not an entire day. A little testing upfront can uncover major system instabilities early on.

Forcing computer components to operate outside of normal specifications comes with risks. Be well aware that overclocking will void any warranty you have. If you play it safe and only increase the CPU voltage by a few percentage points, the overclock shouldn't affect the longevity of your equipment by very much. As long as you keep the temperatures low, everything should be fine.

An overclocked system using a normal fan and heat-sink cooling unit doesn't require much more care than a non-overclocked system. Get a can of compressed air and clean dust out of the case regularly. Go in for a deeper cleaning if the system starts to lock up while running games or other processor-intensive applications. Clear out the case air filters, and make sure to wipe down the CPU heatsink as well as the motherboard northbridge heatsink to get rid of dust that can trap heat.

Are you an experienced veteran with several processors under your belt? What CPU do you have and how high have you overclocked it?

Discussion

283 comments
hurricaner
hurricaner

I am on a Gateway GT5422E Running on Stock Fans with the stock processor (AMD Athlon™ 64 X2 5000+, dual core processor ) Stock motherboard , I switched the RAM over to 2 Gigs(PNY DIMM DDR2 Memory) , i installed a dedicated graphics card(NVIDIA Geoforce GTX 260) i switched the 300 watt power supply over to a 550 watt power supply.it runs great but i think the fans make too much noise so i am going to switch the CPU over to liquid cooling so that the heat from the CPU doesn't cause the whole system to panic(the power supply regulates the temperature inside of the PC with a thermostat so the heat from the CPU enters directly into the power supply and the power supply believes the temperature in the whole case is higher than it actually is.)i pray that this next upgrade that i am going to do will resolve the problem

Wings_008
Wings_008

i managed to OC my P4 3.2Ghz processor to 4.0 with the voltage set to 1.6v with a MSI P35 neo combo and a i-gloo 5710 heatsink (beware P4 run very hot when OC'ed) the golden rule is : to buy a well built and trusted products not the priciest am a college student so i don't have the money to buy a new pc

mehrdad1987
mehrdad1987

Very Cool, thanks Gamespot. Gamespot Is The Best ! ! !, imo

chrisf1
chrisf1

any help on getting it higher i would be greatfull thanks chris

chrisf1
chrisf1

would try higher on cpu but told amd fx62 not very good for overclocking

chrisf1
chrisf1

by the way temps never go over 45 degree's on processor and 60 on graphics at full load

chrisf1
chrisf1

amd fx62@3.2ghz stable,crosshair mobo,4 gig 1066 ddr2 ram,2 terabytes harddrives,1 blu ray+1dvd rewriter,ati powercolor pcs 4870 1 gig o/c @ gpu 800mhz+memory 1005mhz all prime stable etc upgrading to new phenom 2 quad asap,zalman cooler thanks chris aslo runing vista x64 changing to windows 7 rc1

fazz81
fazz81

i.ve had my q6600 quad 2.4mhz overclocked to 3.0ghz for 2 years now and have had no troubles at first i had stock cooler and temps were going up abit to high for me to be happy but i purchased a aftermarket cooler(just make sure it'll fit in your case cause some are huge coolers)after it was installed temps have run well. my advice is to talk on a few forums about overclocking and get to know abit about it before you go changing things, unless you got the money to replace it if you break it. the best i've had my cpu to is 4.5mhz but it was idleing at 70c had to chang it back strait away, when im ready to upgrade my cpu i'll get water cooling and pump it back up and see how long it lasts.

St0Ne4Ge
St0Ne4Ge

"It ceaps my CPU very cold " wow....just wow.

kkkudin
kkkudin

make overclocked make your PC durability going down... make sure u use standard specification before your pc going BOOOMMM.... hahahah....

Pixy64
Pixy64

I got 4 options, 3%, 5%, 8% and 10% i can't use 8% or 10% cause i get blue screen but now i use 5% more power i got Athlon x2 6000+ 3.1GHz but now with 5% overclock i got Athlon x2 6000+ 3.25GHz :)

Pixy64
Pixy64

[This message was deleted at the request of the original poster]

shamarke
shamarke

i know nothing about "overclocking" i just buy new parts!:P

DarthLinux
DarthLinux

Is it actually worth overclocking a cpu? Will it improve performance by much or will it just screw up your cpu. I have a AMD 5600+ X2 2.9ghz Dual Core and I'm wondering if it is really worth risking cpu death for some more power?

aura_enchanted
aura_enchanted

im looking to overclock a pentium d 820 processor (thats the 2.8ghz model). in a stack acer aspier t600 if u want a direct x diag lemme know

matthew483
matthew483

hey, I'm pretty new to overclocking, im running a stock emachine T3256, I was wondering what speed would be safe to overclock to?

unreal_ll417
unreal_ll417

If I overclock my AND duo core 3800+ 2.4 to 2.8 or 3.0 am i going to srcow my CPU up ? I have a mini typone CPU fan. It ceaps my CPU very cold

airwalk_102
airwalk_102

yeah and for abit cheaper you can over clock a intel core 2 duo e4300 to 3.47 with fan cooling and up to i think jus over 3.5 with water cooling which was amazing

Norsee
Norsee

@ arsefacex: I read about overclocking over at IGN, and they gat an E6600 overclocked to 3.4GHz, ON THE FAN INCLUDED TOO! I just thought that was amazing, but i wouldn't recommend trying it with a cheap fan cooling because it might not run for very long.

jACkaTacK1107
jACkaTacK1107

any thoughts on the right way to overclock a core 2 duo @ 2.13 GHz using stock air cooling? cuz i dont wanna screw it up obviously lol

stuckboy
stuckboy

@m_shameel_14 You are not likely to screw up the hardware unless you crank the voltage. Just do what the article says, edge the FSB up in very small increments until you encounter instabilities. It is also good to check what temperature the processor is running at each time you go into the BIOS, as then you will know if it is hotter than it should be. Before you consider overclocking, I would take your PC to bits and suck all the loose dust off it with a vacuum cleaner, then take out all the compnents and individually clean them until you can see your face in them. This can improve cooling considerably.

sam03is_
sam03is_

well i suppose i was one of the lcuky one. I just went into a computer shop to get some RAM installed cause i CBF'd doing it myself adn had a chat with the guy about overclocking. Got the PC back and it had a new high powered fan installed and was overclocked and i''ve been a fan of it ever since.

SoberWarock
SoberWarock

Damn Im just going to get a core duo

behony
behony

simply DONT do it if you do not know what you are doing!

m_shameel_14
m_shameel_14

i want to overclock my system, but somehow, i think me doing it alone might screw it up. its a p4 2.0 Ghz, on an inel d865perl motherboard. sucks, i know. any tips?

possum_lord
possum_lord

I have a 3000 venice and got that to 2.5 on a biostar tforce6100, very good overclocker and cheap at £50, I would reccomend if people are wanting to go a bit more serious then go for an dfi lanparty. for any overclocking help go to http://forums.overclockers.co.uk/

DARTHvayda
DARTHvayda

s939 Athlon 3000+ venice, 1.8ghz stock to 2.6ghz on stock voltage. 2.5ghz 100%stable

SV123
SV123

i have an AMD Athlon 2.6 ghz and i overclocked it to a 3.2 ghz and i think that over clocking is great. i would reccommend to anyone who wants to squeze more performance out of their processor without buying a new processor. but it runs awfully hot though..........................

arsefacex
arsefacex

Oh really? SWEET! I can't wait to get an E6600 then! ty :P

n_w95482
n_w95482

You can probably get over 3 GHz on decent air cooling.

arsefacex
arsefacex

So with a water cooling kit, is it alright to oc a E6600 over 3 Ghz?

xUndress2Killx
xUndress2Killx

Colcon2000 if u want an AMD anthlon over a Core 2 Duo your very crazy, its teh best proccesor out right now. I think its ideal for gaming.

burning_hands
burning_hands

To anyone thinking about overclocking their PC. The information youve just read are the very basics. http://www.short-media.com/review.php?r=300 /\/\/\/\/\ this link has a complete guide on how to overclock the 754/ 939 platform. Its slighly irresponsible of gamespot write this article when it isnt really a complete guide, very brief, they dont even mention memory dividers or LDT which which are both affected when you change the FSB. I wonder how many people have read this and just gone and fried their motherboard and cpu....

haj01
haj01

can u even overclock a intel? or just amd?

Popia20
Popia20

i have a AMD Barton 2500+ and now is an AMD Barton 3200+ 2200MHz .Motherboard is a Asus A7N8X-E Delux.

coolcon2000
coolcon2000

Bah, My PC is too rubbish, AMD Athelon, dunno what make though. But Iwant a PC with a AMD Athelon 64 3200+ 512 RAM, and a good Graphics and sound card. But that sometime can be expensive, oh well...

Sp4c3r
Sp4c3r

Have a AMD Athlon 64 3000 + 2000 Mhz @ 2400 Mhz working great only Graphics Card Overclocking wouldn't work

scratzin
scratzin

I've got two P4's @ 3.0 GHz each under the hood. No need to over clock for me :D

elson0630
elson0630

[This message was deleted at the request of the original poster]

Skinner_Y2K
Skinner_Y2K

Currently running an Opteron 146 @ 2.95Ghz on a DFi UT Sli-D board. But keep getting tempted by a lovely Conroe

Vauxor
Vauxor

AMD 3800+ Retail: 2000MHz @ 2200MHz @ 1.4v on a ASUS A8N32 SLi Nforce4 board. Very easy overclocking with this board.

n_w95482
n_w95482

I don't think he's referring to the socket. He's probably talking about the chipset. Intel does have a bad habit of forcing people to buy the newest, best chipset to use their newest CPUs. I think the C2D's require a 975X board, which are fairly new and expensive. Compare that to pretty much any chipset for Socket 939. Most, if not all, can run chips all the way from S939 Semprons up to a FX-60.

Maslowo
Maslowo

Actually, ksa8907 the new intel core2dual is based on the 775 socket design. If you want to get upset about chip designers switching socket design, look to your beloved AMD with there AM2 design. I do agree with core2dual being a stupid new, they should use something with a flashy X in the name. What do you think?

ksa8907
ksa8907

if anyone knows anything about intel and amd, its that intel operates at a higher speed than AMD, however, AMD has a better layout on the processor allowing it to operate at lower speeds and still outperform intel's higher speeds. So overclocking an AMD does more good than oc'ing an Intel. I do have to say that i was impressed when Intel released the core2duo (a stupid name if i say so myself), because they lowered the operating frequency and now outperform AMD by a considerable amount, but i am very optimistic about the quad-core chips AMD will be releasing at the end of the year, and their new 4x4 technology. If you doubt anything i have writen just research it before you post something trying to bash the truth. Also, whenever Intel releases a new chip they change the mobo more often than Micheal Jackson changes diapers, hahaha! whats the point in making a awesome new chip if you have to buy a $200 mobo along with it. Long live socket 939! at least until the quad cores come out ;p

niacxxi
niacxxi

Intel rocks! the best gaming CPU is intel no matter what. and you can probe it yourself. compare anything you want doing overclocking and intel will beat AMD on every aspect.

Poeticinsomniac
Poeticinsomniac

Ok, first unless you have a conroe cpu...intel sucks, has for years. deal with it. Upgraded to a dual core in may, back when the AMD dual core 4400x2 and above were still 500-1100 bucks. I opted for a 165 opteron with a toledo core (same core as the FX-60) found the right stepping digging through chips on E-bay. $287 for the cpu, $199 for my DFI LP NF4 SLI Dr-Expert and used my existing OCZ GE VX PC4000 ram (512x4). Added a x1800xtx 512 GDDR3 ATI card for $199. Ended up with: memory divider 1:1 =320 HTT, CPU voltage @ 1.425 ram voltage @ 3.6, 2880mhz...on air memory timings at 2-2-2-8 memory divider 166/200 =365 HTT, CPU voltage @ 1.5 ram voltage @ 3.9 3285mhz...on air. memory timings at 2.5-2-2-5 CPU temp doesn't get above 37c under load, maintains 27-28c at idle memory bandwidth is between 8900-9500 mb/s End result for about $700 i ended up with a completly new system that outperformed the FX-60 by about 500mhz for $3-400 less then if i just bought an fx-60. Outperforms every other cpu except the conroe's and has better memory performance then the AM2 DDR2. Any other intel chip especially any of the P-4 line it at least performs 40% better. The single ATI x1800xtx has better performance then the majority of the nvidia cards in SLI mode. 146 opteron with same ram, mother board etc clocked at 3.2ghz on air. That chip cost $90 off ebay. Also have gotten a barton mobile 2400+ up to 3047mhz (265x11.5) on a DFI LP Rev B NF2 with same OCZ ram with the aid of OCZ ram booster, 5 other mobile barton chips and a 3200+ xp with locked multi on various boards (epox 8RDA3+, Gigabyte GA700N 400 NF2. DFI ultra infinity, an Abit and several Asus boards as well. all NF2 chipsets) clocked at 2.65ghz-2980ghz on every one of them, Each chip had only a Hefty heatsink, usually a thermaltake tornado or Big Typhoon. None of the barton chips required more then 1.875v on the cpu. and all of those chips outperformed P-4, substantially better memory performance then the intel boards with DDR2. From all i've seen intel finally did some work and made a good chip with the conroe, but ill be waiting till january when the quad core 65nm AMD chips come out, 4 cores on a single die i suspect will be a bit more impressive then 2 dual cores in a single package. For now i tend to think of the AM2 chips out now in the same way i think of the 754 socket chips, simply something to bridge the gap between the real products.

muppet1010
muppet1010

OCing sounds like a great idea, but im not gonna try it. I have had very little success each time i unscrew the case on my pc. I mean last time i tried to add to extra usb ports i couldn't even do that. They still don't work, so OCing is just a very bad idea for me, it would probably end up with me setting my computer on fire or something(and hence losing a lot more money than i saved). But i was wondering if you were to go in to a local smaller pc shop, not like dixons. Do you think that they would be able to do it for me???

nsx3000
nsx3000

Athlon 64 3700+ San Diego at 255 * 11 = 2.8GHz, 1.39V Abit KN8 SLI

hellogamebot
hellogamebot

how can i o'c my 2.93Mhz intel motherboard with 400 FSB 512MB DDR ram??I have a nvidia 5200Fx graphic card.Anyone ready to help?I am an amateur.