Overclocking Intel CPUs for beginners

Discussion in 'Benchmarks & Performance' started by Elektro Slime, Dec 24, 2004.

  1. Elektro Slime

    Elektro Slime Harware Guru

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    [size=+1]A beginner's guide to overclocking Part1[/size]​

    Warning!: Overclocking can cause irreversable damage to your hardware and will undoubtably void your warranty! Do it at your own risk! This guide is provided for information purposes only, I am not responsible for any damage or injury caused as a result of using any of the information in this guide. You are the only one responsible for your actions!

    So what is this overclocking thing?
    Overclocking is the process of making your hardware run faster then originally intended by the manufacturer. For example, say you have a 2.4GHz processor, by overclocking you can increase that speed to 2.8GHz and possibly higher!

    Is overclocking difficult?
    Well not really.....There are just a few basic things you need to know, the rest involves mostly trial and error until you find the 'sweet spot' of your overclocked rig.

    Why Overclock?
    Well as I mentioned above it's to make your system more specificaly your hardware run faster. Say you are looking to buy a new CPU, the latest one out at the moment is 3.8Ghz(about $600), but your max budget will only allow you to get a 3.2GHz($200ish) processor. So by overclocking you may be able to reach 3.8GHz or possibly more whilst paying only a third of the price!

    Another scenerio you may look at is say, you get the latest and greatest game which requires you to have really high end hardware, but say you only have a so and so system and the game doesn't run that well, by overclocking you may be able to get a higher fps which will give you a overall better gamming experience. I hope you now have a basic idea of what overclocking is.


    What are the risks involved?
    1)You will most likely void your warranty.

    2)You will reduce the lifespan of your computer. Not really much of a problem as most of us use a PC for only like 3 years, so i think the extra performance boost is worth it.

    3)You may damage your hardware either by running too high voltages through your components which may result in a short circuit. There is also the unavoidable issue of overheating. Heat is the number 1 enemy of computer components, I'll discuss ways of takling heat problems later on.

    ======================================================​

    Getting down to basics.....

    When overclocking, the main component you will be dealing with is the processor. From now on im going to refer to overclocking as oc'ing. :) . When you get your processor you'll see it's runnig at a certain speed, say you get a 2.4GHz processor, the 2.4GHz is known as the clock frequency. That means the processor is runnig 2,400,000,000 clock cycles every second. The object of oc'ing is to raise the clock frequecy of the processor so it processes more data per clockcycle therby increasing performance. The formula to find the speed of your cpu is:

    [highlight]FSB (MHz) x Multiplier = Clock speed(Mhz)[/highlight]​

    FSB: The FSB is the Front Side Bus, it is the channel through which your entire system communicates with your CPU.

    FYI when you see a system with a 800mhz fsb it actually has a bus speed of only 200mhz, the reason for this Intel CPUs are "quad pumped", meaning they send 4 instructions per clock cycle. And remember when you're overclocking you shall only be dealing with the real fsb (that is, the 200mhz).

    So for a 3.2Ghz system the formula would be:
    200 x 16= 3200mhz

    Please also be aware that all Intel processors have their multipliers top locked, that is they cant be increased. The upcomming prescott 2M will allow the multipliers to be decreased, this will be used by the Enhanced Speed Step feature to reduce heat output and power usage during periods of inactivity.

    ======================================================​

    So how do I overclock?

    Actually the first question should be "can i overclock?". Basically your ability to overclock depends upon:

    • your motherboard
    • your ram
    • the stregth of your power supply
    • cooling
    • the processor

    For now im going to be focusing on only the mobo and processor. But before I continue let me say that if your motherboard is made by Intel you really won't be able to OC much, in post #9 Steevo mentioned he only got a 4% oc, not much is it? :).

    To really be able to OC you need a good mobo from a reputable company like Gigabyte, Asus,Abit,DFI etc.

    ======================================================​

    The good stuff ;)

    Ok, first turn on your system (duh!). Then get into your BIOS setup, on most mobos this is done by pressing the 'Del' key during bootup. While in the BIOS be on the look out for these setting:

    FSB, RAM Timings, RAM Speed, Ram Ratio and Vcore

    You can usually find them under 'Advanced Chipset Features' and 'Advanced BIOS features' but this can vary from manufacturer to manufacturer, for instance on Gigabyte motherboards you can find all the required settings under the 'M.I.T. (Motherboard Intelligent Tweaker)' menu.

    Since I am going over the basics for the time being heres what you gotta do:

    1.Check the Fsb setting if you have a relatively new system it should read 200 on older PCs it will be either 133 or 100. In our example we'll use a 3.0Ghz processor with 200Mhz fsb and 15 multiplier. So select the fsb setting and press 'Enter'. You will now see a new dialog box with a blinking cursor, in the little text box key in the new fsb you would like to use, say 210.

    so now we have :
    210 x 15 = 3150 thats 3.15GHz! so you have increased your processor speed by 150mhz! woot woot!

    Warning!: you should only increase your fsb in small increments like 5 or 10mhz at a time, or you could seriously damage your system!


    2.After you have upped the fsb to 210mhz exit the BIOS setup (make sure you save the new settings as well) and then reboot your sytem. Once your logged into XP run some programs like prime95 or folding@home and leave it on for about 2 hours or so. If it runs without any problems, that is to say stable. Reboot and perform step 1 agin this time upping the fsb a little more maybe lets say up to 220mhz.

    3. Keep on doing this until you notice any instabilities such as BSODs, system lock ups, crashes constant reboots. Also it is a good idea to back down the fsb a little after you've found the highest fsb possible.

    ======================================================​
     
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  2. Sazar

    Sazar F@H - Is it in you? Staff Member Political User Folding Team

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    nice guide...

    consider using bolded headings for different sections because it makes it easier to read through and also when browsing for specific topics...

    good work though... ;)
     
  3. Elektro Slime

    Elektro Slime Harware Guru

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    thanx ill do that prolly tomorrow or the day after...im pretty busy nowadays with school :chinese:
     
  4. Sazar

    Sazar F@H - Is it in you? Staff Member Political User Folding Team

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  5. Elektro Slime

    Elektro Slime Harware Guru

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    :D and thanx for the reps! :up:
     
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  6. Elektro Slime

    Elektro Slime Harware Guru

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    ok reformatting done and some spelling mistakes corrected. will post next part soon.
     
  7. Perris Calderon

    Perris Calderon Moderator Staff Member Political User

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    I don't knw the first thing about over clocking...this guide will help if I ever get something other then a laptop

    it's certainly nice looking work up there electro...if users post corrections or common issues, go ahead and edit the original post on top with credit for the correction to who ever gives it.

    I'm gonna stick the thread..now go out and do some pimpage
     
  8. Elektro Slime

    Elektro Slime Harware Guru

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    thanx again man! ill get to work on the next bit in a few hours and will post in a day or two.
     
  9. Steevo

    Steevo Spammer representing. Political User Folding Team

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    I run a Intel mobo, and can OC. But the board limits what I can do to a very safe 4%. Also being noteable that the AGP bus can be OC'd, but not at the same time as the FSB. However OC'ing the FSB increases,

    1) CPU speed as it is multiplier based.
    2) RAM interface, as it is FSB based.


    Intel calls OC'ing "Burn In Mode".



    But a very good article.
     
  10. Elektro Slime

    Elektro Slime Harware Guru

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    thanx for the info Steevo, actually i was gonna mention AGP/PCi bus on the next update. But thanx anyways.
     
  11. Elektro Slime

    Elektro Slime Harware Guru

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    damn,i tried to update the first post with more content but then i get a message saying its too long! can someone pliz help me?
    but anyways ill include it here:

    ======================================================​

    Can I overclock from Windows?

    Well yes you can, but it's not something I would recomend. Manufacturers like Gigabyte include their own overclocking software with the motherboard, in Gigabyte's case it's called EasyTune.

    IMO it's always better to OC from the BIOS, you have more control that way and the readings like vcore and vdimm are more accurate.

    ======================================================​

    Can I overclock my AMD CPU in the same way?

    AFIAK this method of overclocking also applies to the older, socket A, Athlon XPs. The A64 is totally different monster and a lot harder to OC.

    ======================================================​

    Limitng factors:

    Here are a few things that can limit your OC:

    • your motherboard
    • your ram
    • the stregth of your power supply
    • cooling
    • the processor

    Another important thing I would like to mention is that every chip is unique. Luck also plays an important part. Even if you buy two identical chips there is no guarantee they will OC the same. One may OC great while the other may be a dud :cry:.

    Effect on PCI/AGP bus


    As stated by Steevo:

    When you increase the FSB, you are actually overclocking pretty much every component on your pc. Although this may seem nice, it is actually a disadvantage. A lot of the components cannot handle the higher FSB and will be come unstable. FYI when buying a motherboard make sure it has a working pci/agp lock . The advantage of this it will 'lock' the speeds of the pci and agp bus at its normal speed so increasing the FSB wont affect it.

    I also should mention that increasing the fsb will also affect the RAM. And like the agp/pci bus running it out of spec can lead to instabilities. I'll go into details later on.



    Vcore

    First of all:

    • Vcore is the voltage to your CPU
    • Vdimm is your ram voltage

    Ok now it gets a little dangerous :dead:. Increasing the vcore too high can reult in your CPU getting fried. But since I don't want that to happen, here are some safe and max vcore settings for the most popular CPU cores:

    Source:
    Extreme Overclockers and other tech sites.

    1.Willamette (Celeron, P4) Core-
    VMAX: 2.1v
    Safe: Not sure

    2.Northwood (Celeron, P4)-
    VMAX: 1.75v
    Save vcore: 1.7v

    3.Prescott (Celeron, P4)-
    VMAX: 1.55v
    Save vcore: 1.525v

    I cannot guarantee you the accuracy of the above info, it would be better if you look up your CPU in Intel' site.

    At some time or another you wont be able to increase your FSB stably no matter what, so here's where the vcore comes in. Upping the vcore will get you a higher stable FSB. Please be aware that when you increase the vcore your CPU's heat output will also increase.

    Important!: you should only increase the vcore in the smallest possible increment and you should never exceed the maximum vcore limit as set by the manufacturer.



    RAM & YOU

    Like the FSB, RAM speed can also be little misleading. Say for instance you have PC3200 which is DDR400, the 400 after the DDR gives you the RAM speed, so its 400mhz. As seen above the FSB is quad pumped, likewise RAM speed is 'double pumped' that is it is sending instructions twice per clock cycle. FYI DDR stands for Double Data Rate.
    In some places DDR 400 is refered to as PC3200, this can be quite confusing at times so here's a list to help you out:

    PC-2100 - DDR266
    PC-2700 - DDR333
    PC-3200 - DDR400
    PC-3500 - DDR434
    PC-3700 - DDR464
    PC-4000 - DDR500
    PC-4200 - DDR525
    PC-4400 - DDR550
    PC-4800 - DDR600

    As I mentioned before increasing the fsb affects the pci/agp bus frequencies, this is also true for your RAM. Say your running a 3.0Ghz P4 with a 200 mhz fsb (quad pumped to 800mhz) and 512mb of DDR400 RAM with an actual speed of 200mhz. So both your FSB and RAM are running at 200mhz.

    So now, say you up the FSB to 240mhz but since the RAM is only rated to run at speeds up to 200MHz, raising your FSB higher than 200MHz can cause your system to crash.

    So what do I do now? You may ask, well here some things you can try out:

    1) Using RAM divider (using a FSB:RAM ratio)
    2) Overclocking your RAM
    3) Buying faster RAM.

    For more information about the following procedures refer the following site:
    http://forums.pcper.com/showthread.php?t=320351



    Heat ain't cool

    Do I really need better cooling? Well... if you own a prescott you should know ;). Thing is all the components in your computer uses electricity (please stop laughing! :mad: ). Also none of these components is a 100% efficient that is, there's some amount of resistance to the flow of electricity in the component. This resistance causes some of the elctrical energy to be lost as heat energy. Therefore the higher the resistance the greater the heat given out. Now heat is one of the greatest enemies of electrical components, too much heat and you could risk frying your machine :rambo:.

    So here's a list of some of the common and the not so common ways of keeping your rig cool:

    1) Air cooling.
    2) Water cooling (plain or chilled).
    3) TEC/PELTIER.
    4) Phase change cooling.
    5) LN2 (liquid nitrogen cooling).
    6) Immersing your mobo in special mineral oils.
    7) Nanolighting.

    Air cooling

    This is basically the use of fans and heatsinks to cool your components.
    Here's link to everything air cooling related:
    http://forums.pcper.com/showthread.php?t=154105

    FYI: If you decide to add some fans in your case make sure that the number of fans blowing air into the case is greater then the fans sucking air out. This helps create some swirl in the airflow, breaking up dead air spots in the case, as well as make to the air a little denser to cool the heatsinks. Also it helps to prevent dust build up in the case.

    Water cooling

    This involves using water in waterblobks to channel heat away from the components through pipes. You also need a pump and radiator. I really don't know much about them :(.

    Phase Change

    You can basically think of it as a mini air conditioner for your CPU which

    TEC/PELTIER,LN2,Nanolighting cooling

    :ermm: ummm.... I really don't know anything abot these maybe except they can cost you in excess of $1,000! Try doin' a google on em. BTW if you do find anything on them give me a shout and I'll add it here :cool:.



    ======================================================​

    more commin soon........stay tuned folks......

    -Slime
     
    Last edited: Apr 24, 2005
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  12. Steevo

    Steevo Spammer representing. Political User Folding Team

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    Rep +++++++
     
  13. Elektro Slime

    Elektro Slime Harware Guru

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    rep for what? including yer name? ;)
    but thanx anyways
     
  14. Steevo

    Steevo Spammer representing. Political User Folding Team

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    Good article.

    To be honest I could care less about my name, or the rep points. Other than they are a way to show repect for or to someone.


    Want mine?
     
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  15. Shamus MacNoob

    Shamus MacNoob Moderator Political User

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    When you say changing the FSB will also up the ram depends most all boards allow for an independent setting for the ram speeds ie: 100%, by SPD, or in a ratio format like 1:1 .. but seeing as when you overclock you want a higher FSB, as high as possible and the best you can have is 1:1 ram to cpu ratio then its ultra important to have ram that has a higher rating if your working on a plus 200 FSB then pc3200 is not the best choice it would be stressed as soon as you go over 200 FSB ...
     
  16. Steevo

    Steevo Spammer representing. Political User Folding Team

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    True.dat

    I have 333 RAM but run PC3200 so I can OC it with no loss of stability.
     
  17. Elektro Slime

    Elektro Slime Harware Guru

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    ok....UPDATE!!!!

    Added some stuff about ram and also little about cooling, check post #11 above. Ill update with some info ASAP. c ya.........
     
  18. SuperModelRobot

    SuperModelRobot OSNN Addict

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    can all pc's support overclocking? Even pre-built ones?
     
    Last edited: Dec 13, 2005
  19. SuperModelRobot

    SuperModelRobot OSNN Addict

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  20. Shamus MacNoob

    Shamus MacNoob Moderator Political User

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    In a simple answer no they cannot.