A beginner’s guide to overclocking

TR Overclocking Guide - Sponsored by Gigabyte

As a PC enthusiast, my desire to overclock is almost compulsive. Pushing clock speeds must be hard-wired into my DNA, because I can’t actually remember the last time my personal workstation ran at stock speeds.

Overclocking isn’t for everyone, though; it can be time consuming and frustrating, and it will almost certainly void your warranty. But there’s a unique sense of satisfaction to be gained from pushing your hardware to its limits and achieving greater performance than you’ve actually paid for. For enthusiasts, many of whom have a borderline obsession with deriving the best bang for their buck, overclocking’s potential is simply too hard to resist.

To help the uninitiated get their feet wet with overclocking, we’ve whipped up a handy guide covering the basics. This is by no means an attempt to document every technique associated with turning up your system’s clock speeds, but it should be a good place to start for newbies looking for their first taste. We’ve chosen to focus our examples and advice on Intel’s Core 2 processors, since they’re a particularly popular choice right now, but many of the basic principles we’re exploring apply to any chip you might want to overclock, including AMD CPUs.

What is overclocking?

Simply put, overclocking refers to running a system component at higher clock speeds than are specified by the manufacturer. At first blush, the possibility of overclocking seems counter-intuitive—if a given chip were capable of running at higher speeds, wouldn’t the manufacturer sell it as a higher speed grade and reap additional revenue? The answer is a simple one, but it depends on a basic understanding of how chips are fabricated and sorted.

Chip fabrication produces large wafers containing hundreds if not thousands of individual chips. These wafers are sliced to separate individual dies, which are then tested to determine which of the manufacturer’s offered speed grades they can reach. Some chips are capable of higher speeds than others, and they’re sorted accordingly. This process is referred to as binning.

There’s considerably less demand for faster chips than for slower ones, though. The Core 2 Extreme QX9650 may be the fastest CPU Intel can produce, but with street prices hovering around $1200, it costs quite a bit more than most folks are willing to spend on a CPU. The Core 2 Quad Q6600, which sells for less than $300, is in much higher demand because it fits within the budget of a greater number of consumers. And demand for low-end chips is even greater still.

Chipmakers often find themselves in a position where the vast majority of the chips they produce are capable of running at higher clock speeds, since all chips of a particular vintage are produced in the same basic way. So chipmakers end up designating faster chips as lower speed grades in order to satisfy market demand. This practice is of particular interest to overclockers because it results in inexpensive chips with “free” overclocking headroom that’s easy to exploit. That’s the magic of binning: it’s often quite generous. A great many of the CPUs sold these days, especially the low-end and mid-range models, come with some built-in headroom.

Overclocking can do much more than exploit a chip’s inherent headroom, though. It’s also possible to push chips far beyond speeds offered by even the most expensive retail products. Such overclocking endeavors usually require more extreme measures, such as extravagant cooling solutions, so they’re a little beyond the scope of what most folks will want to tackle.

What you need

The most important ingredient in any overclocking endeavor is a good chip. If you’re looking to exploit the “free” overclocking headroom made possible by binning, you’re best off looking at lower speed grades. If you’re after the maximum overclock, you’ll probably want to pick the number of cores and the amount of cache that you want, and then select the lowest speed grade available with those characteristics. If you have a choice between chips with different front-side bus speeds, it’s probably best to pick the chip with the lower default bus speed. A slower front-side bus can make life easier for the motherboard, and you may even be able to overclock the processor without pushing the board beyond its specifications.

Overclocking forums are also rife with discussions of specific CPU steppings and batch numbers that have higher success rates than others. If you’re willing to do a little research—and if you can coax retailers into giving you more detailed information on chips they have in stock—you can increase your chances of success. Gathering stepping and batch information is particularly useful if you intend to push clock speeds well beyond any binning freebies.

Of course, success is never guaranteed with overclocking. Your mileage will amost certainly vary, and you might even end up with a complete dud incapable of running more than a few MHz faster than its stock speed.

Just because we’re focused on processor overclocking doesn’t mean that other system components aren’t important. A system’s motherboard, cooling system, power supply, and even memory can affect the success of an overclocking attempt. These don’t necessarily need to be expensive high-end parts—that would defeat much of the value proposition behind overclocking—but you’ll be better off with quality components from reputable manufacturers.

On the motherboard front, you want to ensure that the BIOS has ample overclocking options, including the ability to manipulate bus speeds and system voltages. The more control we have over system variables, the more freedom we’ll have to tweak settings carefully in pursuit of higher clock speeds. Motherboard cooling becomes more important when you turn up clock speeds, as well. You don’t need a mess of heatpipes snaking every which way on the board, but try to stay away from boards with tiny chipset coolers that don’t offer much surface area to dissipate heat.

Ditch the puny stock heatsink (left) for something beefier (right)

Depending on how far you intend to push clock speeds, you may also want to consider beefing up your system’s CPU cooling. Overclocked chips tend to run hotter than those at stock speeds, particularly when you start increasing the CPU voltage, and you don’t want a stock cooler holding your system back. Aftermarket coolers designed for overclocking feature significantly more surface area than the stock coolers AMD and Intel bundle with their processors. Aftermarket coolers also tend to have much larger fans to generate more airflow, often while making less noise. Decent coolers can be had for as little as $30, so they won’t put a big dent in your budget.

We always recommend that users spend a little extra to get a quality power supply for their systems, and this goes double if you want to overclock. Our concern here isn’t getting gobs of extra wattage, but ensuring that the PSU delivers clean power to the system.

Fancy memory isn’t always necessary if you’re looking to overclock a processor, but DIMMs rated for operation at higher frequencies can give you a little more freedom when playing with clock speeds. Memory module manufacturers often guarantee their products to run at higher clock frequencies, even if those speeds aren’t officially endorsed by the JEDEC standards body that governs system memory.

Even more important than individual component choices is having a completely stable system before you dive into overclocking. If you’re building a new system from scratch, stress test it at stock speeds to ensure that everything is working properly. The last thing you want is to burn an afternoon trying in vain to overclock a system hampered by a faulty component that isn’t even stable at stock speeds.

The obligatory warning

Overclocking will probably void your warranty, and it has the potential to damage not only the hardware being overclocked, but other system components, as well. This is where The Tech Report absolves itself of any responsibility for damaged hardware, voided warranties, puffs of magic smoke, core meltdowns, and bruised egos that may result from unsuccessful overclocking attempts. Or, heck, even successful ones.

We should also warn you that this guide covers overclocking through the motherboard BIOS. If you’re not comfortable poking around in the BIOS, you probably shouldn’t be overclocking in the first place.

Finally, before you begin overclocking your CPU, you should start by making a backup of any important data on your system. You may even want to consider using a disk imaging program like Symantec Ghost to make a complete image of your boot partition. We’ve seen more than one OS installation rendered unbootable by file corruption caused by an unstable processor in the midst of an overclocking attempt. The trial-and-error process of seeking a stable overclocked configuration necessarily involves some risk on this front, so make provisions ahead of time.

Basic clock theory

Overclocking starts and ends with clock speeds, and you’ll need to know about several clocks in a system in order to understand how things work. For Core 2 processors, the first clock of note belongs to the front-side bus. The front-side bus, or FSB, links the CPU to the rest of the system, including main memory, storage, graphics, and peripherals. Like several of the key elements in a modern PC, the FSB is a little tricky, because its effective data rate differs from its base clock speed. For example, the Core 2 Duo E6750 is advertised as having a 1333MHz front-side bus. That’s the effective data rate, but the base clock is 333MHz. You’ve got to multiply by four to get the effective bus speed from the base FSB clock. Intel uses the term “quad-pumped” to describe the FSB’s nature. Overclockers tend to refer to the base FSB clock rather than the effective speed, because the base clock frequency is usually the value shown in the system BIOS.

The FSB is notable because processor clock speeds are determined by the product of the base FSB clock and the CPU multiplier. For example, the Core 2 Duo E6750 uses an 8X multiplier with a 333MHz base clock, yielding a processor speed of 2.67GHz on an effective 1333MHz front-side bus. (For AMD chips, the CPU multiplier is applied to the HyperTransport base clock.)

The easiest way to overclock a processor would be to increase the value of the CPU multiplier. However, with Core 2 processors, doing so is only possible with Extreme Edition chips that are far too expensive to be reasonable overclocking candidates for most enthusiasts. Intel prevents users from adjusting the CPU multiplier upward on its other chips. AMD does the same thing with its processors; only its Black Edition and FX chips allow the CPU multiplier to be increased.

Interestingly, it’s actually possible to decrease the CPU multiplier for Core 2 processors. That won’t help with processor overclocking, though, leaving us with no choice but to tackle the front-side bus. This is where it helps to have a CPU whose native front-side bus speed is lower than the maximum FSB supported by the motherboard. Combine a Core 2 that has a native 1066MHz front-side bus with a P35 or X38 Express-based mobo that supports FSB speeds up to 1333MHz, and you have 266MHz of quad-pumped overclocking headroom right out of the box.

Gigabyte’s GA-X38-DQ6 yields control over the FSB and memory multiplier

For the sake of illustration, we’re going to be overclocking a Core 2 Duo E6750 processor on a Gigabyte GA-X38-DQ6 motherboard as we step through the key system clocks. The menu above is typical of many high-end motherboards. Gigabyte labels the base FSB clock as the CPU Host Frequency. The default value for this CPU is 333MHz, but we can change it by setting CPU Host Clock Control to “Enabled” and simply keying in the value we wish to use.

Oh, and let’s hope you’re using a home-built PC with a decent motherboard. Don’t expect to find these menus in the BIOS of your average Dell, folks.

This 390MHz FSB base clock yields an effective 1560MHz bus speed

I generally like to overclock in small increments, increasing the front-side bus base clock in 10MHz steps. Overclocking is usually a very iterative process: set the speed a little higher, test, and repeat. However, for this example, we’ve skipped ahead a little bit, because we know this chip has lots of headroom. If you do the math, an 8X multiplier on a 390MHz bus will get us a CPU clock frequency of 3120MHz or 3.12GHz. That’s… quite healthy. We’ll stick with that for the time being.

Of course, the CPU isn’t the only system element that bases its clock speed on the front-side bus. The PCI Express, PCI, and memory subsystems also typically derive their clock frequencies from the FSB clock. We’ll want to ensure that overclocking the front-side bus doesn’t inadvertently increase the clock speeds of any of these other subsystems, lest they hold back our overclocking attempt. We can manage these auxiliary clock speeds in one of two ways.

The easiest means of keeping these clocks in check is locking them down at a given clock speed, regardless of the FSB clock. Any motherboard with a good suite of overclocking tools should include such an option for the PCI and PCIe subsystems. Sometimes, these options are even enabled by default. In the example below, we’re locking down the PCI Express clock at 100MHz, which is its proper default speed.

Lock that puppy down so your graphics card won’t become a clock speed bottleneck

A much bigger concern is the memory clock, which most often cannot be locked. Instead, the memory clock’s relationship with the front-side bus is usually governed by a single value—a multiplier, divider, or ratio, depending on the BIOS. By manipulating this value, we can keep the memory speed from exceeding the rated speed of our system’s memory modules, even as we increase the front-side bus speed. That’s exactly what we’ll want to do during our initial CPU overclocking attempts: adjust the memory ratio in order to keep the memory clock at or below our DIMMs’ stock speeds. Later on, if you wish, this memory ratio can also be used to overclock your memory, if fiddling with CPU clock speeds isn’t enough to satiate your appetite.

In our example case, we’re using 800MHz DDR2 memory along with our 390MHz FSB, so we’ve set the system memory multiplier to 2X the FSB clock. That should give us a memory clock of 780MHz—a little slower than stock for these DIMMs, so we’re sure overclocked RAM won’t be a source of instability. There’s no real harm in running our memory at this somewhat odd speed, either.

This one’s multiple choice

Setting this board’s memory ratio involves a multiplier much like the CPU’s, but it seems like every motherboard maker does it a little differently. Each chipset has its own quirks, too, like the MCH strapping on this Intel chipset. The ratios can be confusing and may not always behave like you’d first expect, but a good mobo will help. The X38-DQ6’s BIOS even shows us the resulting memory frequency of 780MHz just below the multiplier option.


Like Intel’s front-side bus, DDR memory transfers data multiple times per clock cycle. In this case, DDR’s double data rate means that we multiply by a factor of two. A 400MHz memory clock corresponds to an effective memory data rate of 800MHz. (This 2:1 ratio between the base memory clock and the data rate holds true for all DDR memory types, including DDR2 and DDR3 modules.) Unlike the FSB, however, motherboard BIOSes usually express all values using the effective memory clock, so you shouldn’t have to worry about doing the math.

Putting the theory into practice

Now that we have explored the basics of modifying your system’s clock speeds, let’s talk about putting that theory into practice. Like we said earlier, overclocking is generally an iterative process. You’ll want to start with a relatively modest overclock, save the BIOS settings, and then reboot the system to see if it POSTs and makes it all the way to your operating system. If it does, you’ll want to confirm that the BIOS changes you made have produced the intended result. Fire up CPU-Z to confirm that the bus speeds you’ve set in the BIOS are in effect and yielding the correct processor clock speed. CPU-Z can also be used to check on the CPU voltage, which will become more important in a moment.

Our example overclock was a success!

However, we’ve found that CPU-Z’s voltage readouts aren’t always quite correct. To get more precise insight into your system’s health, you’ll want to install your mobo maker’s system monitoring application, which is usually included on your motherboard’s driver CD. These apps often have flashy or frustrating interfaces, but since they come from the board maker, they should give you correct readings for system voltages, clock speeds, and temperatures. Here’s a look at Gigabyte’s Easy Tune application on our test system.

The board is (pretty much) honoring our request to lock PCIe at 100MHz, and PCI is at 33MHz, as a result

If you poke around a little in Easy Tune, you’ll find a single page that shows voltages, fan speeds, and temperatures all at once.

We’ll want to leave this window open to keep an eye on processor temperatures. Core 2 chips start throttling around 72° Celsius, and I wouldn’t want to exceed the mid 60s under load.

Speaking of load, it’s time to fire up a stability test to ensure that everything is working smoothly. We like to combine a couple of different applications—something like Prime95 to hit the processor and memory in addition to a graphics demo to stress the video card—to ensure that a system is stable. Prime95 will toss out computational errors or even hang your system if the CPU is overclocked too far.

Two instances of Prime95 pinning a pair of processor cores

If you’re running a multi-core processor, be sure your stress testing produces a full load on all your processor cores. You can run extra instances of Prime95 by copying the program executable to another directory and launching it from there. The processor affinity for each Prime95 instance can then be set through the app’s advanced options.

If Prime95 runs stable for five minutes or so without triggering uncomfortable CPU temperatures, it’s probably time to move on to higher clock speeds. If Prime95 throws an error, the system locks or reboots, or you’re treated to Windows’ dreaded Blue Screen of Death, well, you’re going to need some additional help.

You’ll also need some additional magic if you can’t even get that far. As your processor’s clock speed rises with the front-side bus speed, you’ll eventually hit a wall where the system will either refuse to POST, refuse to boot your operating system, or otherwise become unstable. You’ve now exceeded the capabilities of your system, at least with stock voltages.

If you can’t get the system to boot far enough to allow you to modify the BIOS, you’ll probably start to sweat a little, like I do, as the worry begins. That’s never fun. But worry not, because salvation is but a simple step away. You can clear out your overclocked BIOS settings easily. Just find the “clear CMOS” header on your motherboard and slide a jumper onto its two prongs for five seconds or so in order to reset the BIOS to its fail-safe default values. This header is usually clearly marked and located somewhere near the CMOS battery.

Our example board has just two prongs on its header, but many boards have three prongs, with a jumper pre-installed on pins two and three. Moving the jumper to pins one and two will usually do the trick in arrangements like that. However, you’ll want to consult your motherboard’s manual for advice on your particular board’s exact CMOS reset procedures.

After the CMOS has been cleared, the system should happily POST again. You can then go back to your last stable BIOS settings and keep tweaking, if you wish. Here you have the option of calling it a day or pushing on with a little extra juice.

Better living through higher voltage

That’s right, after you’ve hit a wall, the next step in your overclocking odyssey probably involves voltage.

Our example rig gets a minor bump in CPU voltage

Increasing the voltage applied to a given system component usually helps it run at higher speeds. This is particularly true of CPUs, but be careful not to get carried away. Raising processor voltages will make a chip run hotter, requiring additional cooling. More voltage isn’t always better, either. Unless you’re using extreme liquid or sub-zero cooling, most chips tend not to benefit from more than a couple of extra tenths of a volt. Start out with small voltage increase increments and initially confine your voltage fiddling to the processor. Once you’ve applied a little extra voltage through the BIOS, shoot for the last front-side bus speed that failed to see if it’s stable. If system stability gets worse when higher voltages are applied, it’s time to beef up your cooling or back off to lower voltages.

When you reach a point where increasing the CPU voltage doesn’t result in higher stable clock speeds, turn your attention to chipset and front-side bus voltages. These can be increased, as well, and they tend to be most helpful at higher front-side bus speeds where you’re approaching the limits of the motherboard’s capabilities. In my experience, you’ll run out of CPU headroom long before your motherboard gives up, but it’s worth tweaking the mobo a bit just in case.

For the record, our example CPU eventually turned out to be quite happy at an astounding 3.64GHz at 1.3875V, using nothing more than a stock Intel air cooler. We stepped through at least 10 to 15 different clock speed and voltage increments in order to reach this speed, recording info as we went.

Holy Moses!

Be sure to document all the settings you used, your system temperatures, and the results of your stability testing along the way. This information will come in handy when you’ve determined the limits of your processor and motherboard. For some, the point of overclocking is to achieve the highest speed possible, at any cost. However, for others, it’s about reaching an optimal clock speed with the best blend of performance, power consumption, and temperature—the sweet spot, if you will. This sweet spot may give you 90% of the highest stable clock speed your processor can achieve, but do so without the need to increase voltages or significantly impact temperatures. I’ll take that over bragging rights any day.

When you settle on a final configuration for your system, you should conduct a longer stability test, otherwise known as a burn-in. This test should peg your system at full utilization for several hours at the very least to ensure that everything is perfectly stable. It’s a good idea to log temperatures during this test to ensure that prolonged periods of heavy load don’t overwhelm your system’s cooling solution.

Extra credit

Successfully exploiting the “free” overclocking headroom available with most budget processors can act like a gateway drug, pulling you deeper into the obsessive underbelly of the overclocking world. And that’s not necessarily a bad thing. While most folks will probably want to limit their overclocking exploits, the more adventurous will find no shortage of options for further advancement.

We’ve only dealt with basic processor overclocking today, but if you’re willing to dole out some cash for a fancy water or sub-zero cooling system, you should be able to push your processor’s clock speed even higher. Other system components can be overclocked, as well. Overclocking your memory is probably the easiest to tackle next, since it can be done by manipulating bus dividers through the motherboard BIOS. For this, you’ll want some fancy memory modules rated for operation at higher speeds; budget or generic DIMMs tend not to fare well when pushed beyond their specifications.

Once you’ve pushed your CPU to its limits, your system’s graphics card awaits

Graphics cards are also prime candidates for overclocking, and you can push them to their limits without leaving the comfort of Windows. Nvidia’s nTune system utility, for example, allows users to set GPU core and memory clock speeds. nTune also has a built-in stress test that can be used to validate the stability of a given configuration. There’s no shortage of aftermarket cooling solutions for graphics cards, either.


Overclocking is almost a rite of passage for enthusiasts. Squeezing extra MHz from otherwise inexpensive processors speaks loud and clear to our drive to maximize the bang for our buck. If we can take advantage of market dynamics that force chip makers to bin processors fully capable of running at higher speeds to meet demand for low-end chips, then maybe we’ve stuck it to the man, as well. What’s not to like about that?

If we’ve whetted your appetite for more, be sure to check the Overclocking, Tweaking, & Cooling section of our forums for more discussion of all things overclocking.

TR Overclocking Guide - Sponsored by GigabyteThanks to Gigabyte for making this guide possible. If you think you’ve got a handle on this overclocking thing and are ready to show the world what you can do, head on over and check out Gigabyte’s online overclocking contest. Gigabyte is giving out over $10,000 in cash prizes to its winners, with a top prize of $2500 for turning in the best overclock. With eight cash prizes and a host of other goodies at stake, including some very nice motherboards, your odds may be better than you’d think. Be sure to register and to mention TR when you do, if you will. We’re hoping you guys will show up and represent us well in this one. Don’t let those wankers from Tom’s and Anand’s hog all the prizes.
Comments closed
    • TheFreshMaker90
    • 13 years ago

    Hey there Geoff, I just wanted to say that your beginner’s guide to overclocking, was immensely helpful and without a doubt the best guide regarding overclocking I have read thus far simply because you assume that the reader has no prior knowledge on the topic; something a lot of tutorial based writers often neglect, plus from my experience, overclocking can be as simple or as complicated as the user wants it to be and you definitely highlight this fact and it shows in your writing; your guide is simple enough for beginners to understand yet it manages to delve into the more complex aspects of OCing, so kudos on that.

    Anyway buddy, keep up the good work yeah?

    • JWH420
    • 13 years ago

    I also need to add that i enjoyed this article. Learned alot although i wish someone would compile a down to earth dictionary for the multitude of terms used by all the different companys to describe the same things. Another thing I wish someone would share is more of these great programs like Prime95, Ntune, and CPUID dont know how i lived without them

    • 13 years ago

    Great article, Ive never really gotten into the whole OC thing I just buy the best I can at that time and upgrade about every year or so but Im tempted to try this stuff out just for fun. I just picked up a Phenom 9600 black box edition and I think ill start there.

    • Tommyxx516
    • 13 years ago

    I have a P4 @ 2 GHz. I overclocked it to 512 GHz. I managed to upgrade the RAM from 1 Gigs to 5 TBytes. I overclocked my quadcore Nvidia 990000 videocard to 16 GHz. Now, my spreadsheets open 0.00023 seconds faster. I tried playing Crysis4. On default graphics speed, it only ran at 1400 frames/second, now I get 1500 frames/second – I can totally see the difference!

    • ChrisDTC
    • 13 years ago

    Im home for Christmas right now, but my rig at school is a GA-P35C-DS3R with a B3 Q6600, so I plan on entering.

    Right now Ive got it running at 3.0, and Ive tried to poke up higher and I think its my cheap G.Skill memory thats letting me down. Plus the B3 version of the Q6600 runs hotter than the G0s most people have, so I dont know if Ill start hitting a thermal wall too.

    Hopefully my fellow gerbils will have useful advice.

    • albundy
    • 13 years ago

    great cezars ghost! you got over 70% overclock on the e6750 on stock cooling? thats amazing…

    I’ve been hearing about a black phenom. playtime will be fun next year.

    • Crayon Shin Chan
    • 13 years ago

    I choose my components based on price, unfortunately. As a result, I have never seen such a plethora of awesome overclocking bus options as well as voltage settings. Colour me green.
    Also, my memory was always stock stuff, which probably didn’t let me overclock that much.
    Celeron 600@675
    Athlon XP TB-A 1533 (unlocked, but not overclocked… even when I dropped the multiplier and raised the FSB, there was always some small thing that would push the system over the cliff)

    • Vera
    • 13 years ago

    Can someone tell me why lowering the multiplier and raising the FSB is bad?

    I have an Opteron 185 Stock 200Mhz x 13 Multi = 2.6Ghz

    Can’t get any higher unless i drop it down to 233Mhz x 12 Multi = 2.8Ghz

    and so on…

    Do i even have any other overclocking options without having unlocked multipliers?

      • Flying Fox
      • 13 years ago

      Who told you it is bad?

        • Vera
        • 13 years ago

        Well, not ‘bad’ i guess. but i asked somewhere on the fourm and someone told me to leave the multiplier at its highest. I guess my question is what are the cons of lowering your multiplier?

          • BobbinThreadbare
          • 13 years ago

          If you’re trying to overclock the chip. lowering the multiplier is usually counter productive.

          Obviously, you have an exception to this “rule.”

    • fpsduck
    • 13 years ago

    Hmm, how about TR Gigabyte Volar review?
    It’s in the picture already. πŸ˜‰

    • Aphasia
    • 13 years ago

    Ahh, good times when one was forced to overclock because the higher speed grades was just too darn expensive. Nowdays speed is cheep and overclocking is just a good way to pass time and a “because i can” thing. Not to mention that i value stability and silence above all right now except when im gaming.

    Just the other day i actually threw out my Athlon k7-500. I never did overclock that sucker as i in part didnt want to pry the casing off, or get hold of en overclocking card to use on the extra piece. Bad move as it turns out. Before i tossed it out i took the casing off, its worthless anyway. And lo and behold. Even some of the earlier 500Mhz athlons that came out was really K7-650 ones.

    Oh well, might try it on the next workstation, depending on how it performs.

    • ludi
    • 13 years ago

    This article takes me back. Specifically, to a K6-2/400 that ran at 504MHz for a couple months before destabilizing…

    • willyolio
    • 13 years ago

    next up: overclocking the Killer NIC.

      • BoBzeBuilder
      • 13 years ago

      I’d much rather see an article on Ageia PPU overclocking.

        • bthylafh
        • 13 years ago

        Overclocking your power supply.

          • Inkling
          • 13 years ago

          I hear you can overclock your mouse pad. Somebody out there’s doing this in quantity and marketing them as, uh, what’re they called… mousez, rodentz, rat…

    • Ruiner
    • 13 years ago

    Nice article.
    Stuff I’ve oc’ed over the years:
    Celeron 400@498
    Celeron 366@550
    CuMine P3 700@933
    Tualatin 1.0@1.3
    Duron 600@950
    Mobile Barton 1.8@2350
    Mobile 754 K8@2.6
    current: Brisbane 3600×2 (1.9 I believe) @2.95

      • chronic boot failure
      • 13 years ago

      1.8, I think…

    • TurtlePerson2
    • 13 years ago

    Good stuff, I stopped my overclocking before messing with voltages until now…

      • Darkmage
      • 13 years ago

      Same here. And I have a fancy-schmancy watercooling setup already on it. After all that trouble, I suppose I should overclock it just to see what I can wring out of it.

    • Meadows
    • 13 years ago

    That has to be the biggest chunk of metal I’ve seen since Titanic.

    I’m content with stock coolers, in fact I’m particularly impressed by intel’s stock solution.

      • Ruiner
      • 13 years ago

      Stock coolers are ok for stock chips, but not if you overvolt and want a modicum of silence.

        • Meadows
        • 13 years ago

        Almost all coolers are so silent I couldn’t care less.
        I have a freaking sound system plus a subwoofer, nobody gives a poo whether you can hear a lonely fan (you can’t). No, I don’t use the PC for quality movie playing where silence is important.

    • ReAp3r-G
    • 13 years ago

    that is indeed a 100% unadulterate truth πŸ™‚

    • donkeycrock
    • 13 years ago

    i just oc’ed my e2160 from 1.8 to 3.5 ghz 89% oc, best cpu ever

      • Meadows
      • 13 years ago

      I hope you’re aware of the fact it’s a 94% overclocking.

      • Ruiner
      • 13 years ago

      Very nice. What cooling/volts?

    • Thresher
    • 13 years ago

    Thank you so much for this guide.

    My early experiences with overclocking back in the 90’s did not go well, so I gave up on it. I’m going to try it again now.

    • Flying Fox
    • 13 years ago

    Any plans to address overclocking CPUs from that other manufacturer? I can see those fanboys rubbing their hands to blast this about “biased” and whatever other bad words they can come up with.

      • DreadCthulhu
      • 13 years ago

      Overclocking AMD processors isn’t that different Intel ones; there is probably as much variation within different companies BIOSes on the same platform as there is between AMD and Intel motherboards. Unless you are talking about overclocking VIA chips πŸ˜‰

      Anyways, I am putting together an Athlon 64×2 4000+ machine for my sister & her fiance, but I might pull a switcheroo and give her my Core 2 E6300 + mobo – since my E6300 won’t overclock over 2ghz, while this Athlon x2 is at 2.8ghz so far (am going to restart, and test 2.9 in a minute) and I haven’t even fiddled with the voltage yet. And it is only 35 C at load with the stock cooler on it.

    • Fighterpilot
    • 13 years ago

    Nicely done article there Geoff.
    Intel’s Core 2 processors O/C like crazy but they get hot after 3.4Ghz or so.Aftermarket cooling is a must for those going higher if they want a stable system.
    I was wondering if TR is planning a look into the Extensible Firmware interface which is inching its way(it seems) towards broad release?.
    Might be best if they let Apple do the interface :))

      • indeego
      • 13 years ago

      Yeah because I want thousands of security holes in my overclocking interfaces, all the while shrouded in round shiny reflective buttonsg{<.<}g

        • derFunkenstein
        • 13 years ago

        Actually, the entirety of Apple’s EFI interface consists of one hard drive icon with a Windows logo/X logo/Penguin for each bootable partition it finds, any bootable CD’s in the drive(s), a “netboot” icon if it finds an OS X server with a bootable image, a refresh button, and a “go” button. No reflective/lickable buttons, no security holes, no nada. So braindead easy, you could even do it. πŸ˜‰

    • gratuitous
    • 13 years ago

    Very nice, very nice. If you keep this up TR well may well be in danger of becoming known as the guide to all things PC.

    Love the -[

      • Flying Fox
      • 13 years ago


        • Captain Kitt
        • 13 years ago

        *[<"The processor affinity for each Prime95 instance can then be set through the app's advanced options."<]* Yah, it had me scratching my head. Awesome job overall. There are many guides on the internet on basic overclocking, but none are even close to as well written as this. Nicely Done.

    • ReAp3r-G
    • 13 years ago

    i find it pretty odd that some E4400 owners can OC to 3.2 and i can’t hit 3.15 without the system refusing to POST and resets back to default BIOS settings…from the guide I THINK i can conclude that its the RAM thats holding back the process

    btw i have a question, do you need to add an overvoltage to the northbridge (which in the BIOS is MCH or something of the sort?)

    thanks for the guide TR, i hope you guys come up with more guides πŸ™‚

      • Flying Fox
      • 13 years ago

      I guess Dissonance missed putting in the “YMMV” disclaimer on the first page? It has to be in. YMMV is overclocking 101.

      • Nitrodist
      • 13 years ago

      Heeyy, what’s wrong with the forum sticky? πŸ˜€

      edit: oops, meant to reply to you FF. Why can’t these posts have a delete function, damn it!?

        • gratuitous
        • 13 years ago

        my sentiments exactly.

          • Inkling
          • 13 years ago


    • indeego
    • 13 years ago

    Guess I’m lazy. I just use the software o’clock utilities that come with the manufacturer. Gaudy, yes, but fiddling with BIOS lost it’s luster a ways backg{<...<}g

      • Hance
      • 13 years ago

      Meh all overclocking should be done at the bios level.

        • bhtooefr
        • 13 years ago

        Unless, of course, you can’t overclock at the BIOS level.

        My first overclock was a modest 504 MHz on a 466 MHz Celeron. (The CPU was perfectly stable out to 525, but the sound card quit working once I got the FSB faster than 72 MHz.)

        I wouldn’t have been able to do it without CPUFSB, as the mobo was an HP mobo, and had no BIOS overclocking options.

        Anyway, another point, although it might not apply to Core 2 Duos… if your mobo has more room to go, but your CPU doesn’t, lower the multiplier (that is, there actually IS a reason to lower the multiplier when overclocking) and keep ratcheting the FSB up. Then, you’ll get faster memory access, too (well, OK, RAM speeds are decoupled… but the maximum performance is still improved.) I had a Pentium MMX system that I attempted an overclock that way on, although it failed, because the graphics card couldn’t handle the 75 MHz FSB. (I would have just increased the multiplier, but the 233MHz Pentium MMX was top-locked, so no overclocking for me. Besides, memory capacity was the bottleneck on that system, not the CPU, so it wasn’t like the overclock was going to do much for me anyway…)

          • Flying Fox
          • 13 years ago


            • bhtooefr
            • 13 years ago

            I did. It was saying the exact opposite, that a bottom-unlocked multiplier is useless for overclocking, I do believe, which is why I said that it’s NOT useless. πŸ˜‰

            • Flying Fox
            • 13 years ago

            When I first read it I took it in the context of “the top-locked multiplier will not get you higher clock”, at least it made sense when I read it in the morning!

        • indeego
        • 13 years ago

        Even on the fly overclocking? Many of us only wish to OC 1% of the time we use a machineg{

    • Entroper
    • 13 years ago

    Holy CPU coolers, Batman!

    I like these guides. Are more on the way?

      • JWH420
      • 13 years ago

      Im with Entroper… that thing looks like someone stole a Holley intake design from the musclecar lab

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