OverclockingGuide

ShscWiki :: LogIn :: PageIndex :: RecentChanges

Overclocking Guide

by pik_d

Table of Contents

I. Dangers of Overclocking

II. Before You Begin
>a) Power Supply
>b) Case and Fans

III. Helpful Software
>a) Drivers
>b) Hardware Monitoring
>c) Hardware Testing
>d) Windows GUI Overclocking Utilities

IV. CPU, RAM and Motherboards
>a) Terms Used
>b) Cooling
>c) Overclocking
>d) Choice Picks

V. Graphics Cards
>a) Terms Used
>b) Cooling
>c) Overclocking
>d) Choice Picks

VI. When (Not) to Panic

 Table of content 
Overclocking Guide
I. Dangers of Overclocking
II. Before You Begin
A) Power Supply
B) Cases and Fans
III. Helpful Software
A) Drivers
B) Hardware Monitoring
C) Hardware Testing
D) Windows GUI Overclocking Utilities
IV. CPU, RAM and Motherboards
A) Terms Used
B) Cooling
1) Air Cooling
2) Thermal Paste
3) Water Cooling
C) Overclocking
1) CPU Overclocking
a) Problems?
b) Can't get as far as you think you should?
2) RAM Overclocking
3) Mixing the Two
D) Choice Picks
V. Graphics Cards
VI. When (Not) to Panic



I. Dangers of Overclocking

Don't read this guys it'll never happen to you

Nothing in this guide is a promise except for this next sentence. If you are stupid you will break something, and I am not taking responsibility for your stupidity. This guide is being written in good faith that you understand the dangers and consequences of running your computer above and beyond specifications. Any overclock, no matter how slight, has a chance of cooking your system, this cannot be stressed enough. The chances start incredibly small, but they are STILL THERE. The further you go, the more likely you are to break something, but also the bigger the reward (and that's why you're reading this). If you're willing to take these risks, read on.


II. Before You Begin

Fuck this shit, full speed ahead!

Almost every piece of hardware (disk drive excluded) are important when considering your ventures into overclocking.





A) Power Supply

One of the most important pieces of supporting hardware. If you only get one good quality piece of hardware, it better be this. The most obvious rating of a power supply, maximum sustained wattage, is not the best one. At best it is a good ballpark figure, and even then I would advise against using this measure. What you really need to look at is the amperage on the rails. The 12V rail is the rail you care about, given that it powers both your CPU and Graphics card, the two components that draw the most power.

- How Many Rails? You've probably heard about having “Dual Rails” in a power supply, and you have even have heard that they provide more stability. In short, they don't. This may have been true when the 240VA standard was introduced and required multiple 12V lines, but high quality power supplies with one 12V line are not crippled in any way by their design.

- How Many Amps? Yes, I already said that looking at power wasn't a good indicator of a power supply, and looking at amps on a specific rail is effectively looking at how many watts that rail can supply. (Watts = Volts * Amps, or P=V*I, however you choose to see it). However, looking at the rated amps on the 12V rail is a good indicator of how “strong” the power supply is, so long as it's a good brand.

For a single graphics card and CPU (multiple cores included), a good number to aim for is 400W combined. The Corsair 450VX (pictured above) recommended in the Parts Guide thread is rated for 33A on the single 12V line for a total of 396W on the 12V line alone. For multi-graphics card systems, I would recommend no less than 550W on the 12V line(s).

For those of you gawking at these outrageous figures, keep two things in mind. First is that this guide is for overclocking, where power requirements will NOT stay within the standard thresholds quoted by manufacturers. Second is that even if a power supply is rated for 33A on the 12V line, it will not “want” to stay sustained at 33A, so some headroom is necessary, especially when combined with the first point.

- And Getting Power to the Components? The last thing you will need to keep in mind when choosing a power supply is the cables it supports. Until very recently the PCI-e power rating was 75W from the slot, and 75W from each external connector. The new PCI-e 2.0 standard dictates that both of those numbers are doubled to 150W. A 6-pin PCI-e connector, found in most power supplies on the market can only support 75W, where the newer 8-pin (or 6+2-pin) can supply the full 150W that may be needed for current and future cards.

Not only do you have to make sure you have the correct connectors, but also enough of them. Most cards, to date, only use one 6-pin connector. The 8800GTX uses two however, and the HD 2900XT has space for one 6-pin and one 8-pin connector, however it only requires two 6-pin connectors to run. Yes, a 6-pin will fit in an 8-pin slot, but will of course only provide 75W.


Recommended Power Supply List
Oh god just tell me which one to get!


A more in depth post of PSU recommendations can be found here. Keep in mind this is tier 1 through tier 4 of what is considered to be “high end”. Most of what I am recommending is in tier 3 and 4, simply because I doubt anyone reading this will need a $300 1200W power supply. In short, if it in that post, it's probably a good quality power supply. Also that post is not maintained by me, therefor I do not consider myself responsible for what it suggests.






B) Cases and Fans

I am very hesitant to tell people what case to get, as it is as much a display of personal preference and almost a reflection on yourself as it is a house for the rest of your components. Myself, I have a Lian Li (pictured above), but of course something like this isn't for everyone.

Things you should look for in a Case:







Recommended Case List
I'm just going to lift the Case recommendations from the Parts Guide thread:




As for fans, front and side goes in, top and back go out. Simple as that. Logically, bigger fans can push more air at lower speeds, which means less noise. Keep this in mind when case shopping.


III. Helpful Software

Helping you break stuff, that is

Not surprisingly, I'm going to try and keep all useful software I can think of here. Not all of it is out of beta, but I have used all (OK, most) of it at one point or another. I will try to link to common areas instead of direct download links, so when newer versions come out the links don't break.


A) Drivers

Get the latest versions here:







B) Hardware Monitoring

This group of software is to do nothing but see what the hell is going on with your system








C) Hardware Testing

This group of software will test the stability of your system, simple as that.










D) Windows GUI Overclocking Utilities







IV. CPU, RAM and Motherboards

Thank god! Finally what I came to read! Wait... what is this shit?

Finally indeed. As of writing this, this is on top of page FIVE of a word document. Shesh. We'll start off first with some terms I'll be using.


A) Terms Used













1.3-1.5V






B) Cooling

Put simply, stock cooling sucks. Yeah, it's fine for your every day needs at stock speeds, but for overclocking your generic stock cool will not hold up to aftermarket coolers. If you only looking for a little bump you should be fine with the stock cooler, but if you've actually read this far, you probably feel entitled (with good reason) to a bit more.

1) Air Cooling

To put it simple, aluminum is cheaper, lighter, but less conductive of heat, copper is heavier, more expensive, but better at conducting heat. A copper cooler of the same design will 100% always yield cooler temperatures than a aluminum cooler (assuming all other variables are somehow equalized).

That said, heatpipes have made it so that copper isn't necessary to have a good heatsink, though most do still have copper as the base. Long story short, heatpipes work by using water convection to transfer the heat more quickly to the fins of the heatsink. You want heatpipes on your cooler. Copper is desirable, but not as much.

Recommended Heatsink List








2) Thermal Paste

Thermal paste is the “goopy” stuff between a heatsink and a processor. This stuff is absolutely necessary, as it fills in the microscopic gaps that are on the metal surfaces of the two aforementioned pieces of hardware. I believe stock heatsinks come prepackaged with a sort of thermal tape, this will do the job, but not as well as aftermarket thermal paste.

Recommendations Thermal Paste List




3) Water Cooling

I will say right now that I have no experience with watercooling, and will not even try to pretend I do. If someone else can write up something (and make me believe they know what they're talking about) I'll post it in this spot. For now, you're on your own. However, I have heard that bundled water cooling kits are not as cost effective as buying the separate parts yourself. But I can't help you either way. THIS MEANS THAT IF YOU CAN MAKE A PRESENTABLE GUIDE, I WILL POST IT HERE.


C) Overclocking

WOOO WOOOOOOO TRAIN STOPS HERE!!

First note: WRITE EVERYTHING DOWN! This means Voltages, multipliers needed for certain speeds, MHz, dividers, overall speeds, timings, everything!! Having this information referenced will make your life so much easier as you start trying to set everything up as you want it.

Finally, the only section you want to read, and I'm only halfway down page six in this word document. Hopefully the past sections have given you enough preparation so that you don't blow up anything while reading this one. First I think I'll restate that by following the advice here YOU ARE OPERATING AT YOUR OWN RISK. Stuff could die, your mom could totally get pissed at you for blowing up her new computer you constructed completely by parts bought off Newegg. Do not try and blame me, I've given you enough warning.

Overclocking is an art form so far as I am concerned. Sure, there are finite amount of settings that you can pick in a BIOS, but with every single CPU, stick of RAM, motherboard, and video card having different limits and tolerances, the maxed out settings used on one system will not work the same as they do on another. You'll have to find the limits of your CPU and RAM, then figure out how to make them both happy. You can pick one to start with, it doesn't really matter which, or you can attempt to overclock them both at the same time. When you do this you'll most likely hit a point where you get system instability that you have no idea where it's coming from. I'll start with overclocking the CPU first, since it's alphabetically first.


1) CPU Overclocking

The easiest way to isolate the CPU is to set the RAM at a really low memory divider. This will allow the CPU to continue upward in speed until it reaches it's own wall.

Some CPUs can have their multiplier changed. Most that can have it changed can only have it changed in the downward direction. Some of this is so the CPU can be throttled. Some of it is because having a CPU with it's multiplier unlocked both upwards and downwards is reserved for only the Engineering Samples (ES chips) and the Flagship CPUs, such as the QX6800.

For the purposes of overclocking just the CPU, we don't want to mess with the multiplier (unless you have a CPU with multi's unlocked up and down). We only want to mess with the Bus speed. Either FSB for Intel processors and older AMDs, or HTT/HT Link for newer AMDs for now. That and Vcore. (you guys read the Terms Used section, right?).

Here's a quick reference for maximum temperature and Vcore for the two current lines of processors out. For AMD 64's, 50-55°C is the limit, for Intel Core 2 CPU's, I believe up to 70°C is considered safe, but I'd feel really uncomfortable with it above 60°C. In terms of voltages for AMD 64's 1.5V is considered the maximum “safe” voltage for air cooling. You can go up to 1.6V if you want, but just beware of the greatly added risk. Even if it checks out as stable now, it could seriously degrade the life of the processor. With Intel Core 2 processors, I'd recommend keeping the voltage below 1.4V. If you have a processor I haven't mentioned, I'd keep it within .15V of the stock voltage as a safe rule. Ask though, and I'm sure someone will give you a recommendation. For a more in depth look at safe temperatures for Core 2 processors, this guide has been recommended by maninacape.

Back to overclocking the CPU. You have SuperPi and SP2004, right? This is when you get to use those. Generally it's best to go up by only 2-4MHz per step, but to be honest on your first step , a 5-10MHz increase on the bus still leaves a good chance that you'll boot fine. (of course if it doesn't boot, you know what to do because of the last paragraph). While it may be enticing to make bigger steps to make it go from 2700MHz to 2800MHz in one fell swoop, it's a better idea to take smaller steps.Between each step, however big you make it, you should run through a 16M or 32M run of SuperPi. 16M will be quicker, 32M will be more demanding. While doing all this, I would recommend keeping a handwritten chart of what speeds you can get at what Vcore (both selected Vcore in the BIOS, and Vcore read from the BIOS). This will give you a good guage as to your CPU's abilities. When you get to a point where you're unstable in SuperPi, back down about halfway between this speed and the last speed you were at, until you find the fastest it can go while keeping SuperPi stability. For the purposes of clarity and ease of troubleshooting, only raise the Vcore when your CPU cannot increase in clock speed anymore. You will eventually notice that as you raise Vcore each time, you'll get less and less of a speed boost. At this point is basically as fast as your CPU can go with the current cooling. Congratulations! Make sure this speed and Vcore is well documented.





a) Problems?
And you will have problems

The first section will cover what to do if your system fails to boot, while the second and third sections will cover what to do if you “feel” like you're being held back by some sort of “mysterious force”.

If ever you get to a point where your computer JUST WILL NOT BOOT, and you're screaming around like a headless chicken because your mom wants to check out her email after this episode of Desperate Housewives is over, don't panic. Open your case (and should there be no ill smells tipping you off that something is wrong), use a flashlight to locate the battery (pictured above). Somewhere around the battery you'll find a jumper labeled CMOS (much like the one in the picture, though it may not be that close to the battery).

This details how to reset the CMOS/BIOS using jumpers, it is the shorter of the two methods. - credit to Imyu for updated version of this procedure
  1. Power down and unplug the computer.
  2. Press the power button, this will discharge the capacitors (charged capacitors can shock, and kill if enough current is stored)
  3. Switch the jumper position from 1-2 to 2-3. ie: [o o]o to o[o o]
  4. Wait 5-10 seconds, then move the jumper back to the original position.
  5. Plug the computer back into power, and restart the system (successfully we hope)


This details how to reset the CMOS/BIOS by actually removing the CMOS battery, and takes more time and should only be used if you cannot locate the jumper I talk about above.
  1. Power down and unplug the computer.
  2. Press the power button, this will discharge the capacitors
  3. Remove the CMOS battery from it's location. You should be able to pop it out pretty easily. If you can't, it may be soldered to the motherboard and you'll have to resort to trying harder to find the CMOS jumper.
  4. Wait around 30 minutes, and put the battery back in.
  5. Plug the computer back into power, and restart the system (successfully we hope)
  6. If it does not restart, start over from step 1, but wait about an hour. If this fails, something else is likely wrong.


b) Can't get as far as you think you should?



The following 915/925X section was composed by ChubbyChimp
"For summarizing purposes, if you are running a 915/925X chipset based motherboard and cannot clock much past a 10% gain on the CPU, look here. If you aren't running a board with one of these chipsets, this doesn't apply to you.

(NOTE: if you have an Asus 915/925X board, this most likely doesn't apply to you since their motherboards from this line automatically optimize the PCI-e frequency on POST.)

For some odd reason or another, Intel decided that on the 915 and 925X motherboard chipsets they would implement limitations on their ability to overclock past 10% over stock. If one tries to overclock their CPU past this limit on a 915/925X based motherboard, the system fails to POST, or in some instances randomly crashes during/after POST. A good example of this issue is if you are having problems surpassing around 215-217MHz on your FSB (in this case, 200MHz stock Pentium 4's), even after increasing the Vcore. The culprit in this case is the PCI-express frequency. This setting should be found somewhere in the BIOS along with the CPU settings and defaults at 100MHz. Bumping this value up should drastically increase your CPU's ability to reach higher FSB settings. The basic ratio to stick to is a 2 to 1 ratio of the FSB to PCI-e frequency; although, there may be some small discrepancies depending on your board. In this case, the best thing to do is the classic trial-and-error routine to see how high you can get the FSB on a certain PCI-e frequency setting.

But before you go out and start cranking this setting to its max, you need to understand the consequences of increasing this setting. Firstly is it HIGHLY recommended that you NEVER increase this setting above 120MHz on any board as it will cause severe system instability, especially on a computer running SATA devices (the SATA bus is extremely sensitive to this, so be careful). Secondly, anything that is on the PCI-e bus will be impacted by this, including the PCI-e x16 VGA port. If you are experiencing video errors, or just the inability to boot even though you are below 120MHz on the PCI-e frequency, you may need to increase the PCI-e voltage (sometimes labeled as AGP/PCI Express Voltage) which defaults at 1.5v. My experience has shown me that it probably isn't a good idea to set it much higher than 1.7v, and that setting this to 1.7v will give you a max of 118MHz on the PCI-e frequency, although YMMV. Here is where it gets a little tricky. Video cards can sometimes be quite sensitive to the voltages you apply. If you have a new-ish ATI card, setting this up to 1.7v shouldn't do too much and may give you the added benefit of being able to clock the card slightly higher (and may increase temperatures); however, NVIDIA cards are generally much more sensitive to this change in voltage. Either way, be careful, take it easy, and back off the voltage if you get POST or video errors. Also, if your other PCI-e peripherals fail to work after this, you are SOL and need to revert back to default settings. My rule of thumb is that if you are running anything in the PCI-e x1 ports, it's probably not a good idea to toy with these settings much, as they may or may not damage them (this, of course, also applies to your video card even though they are a little more tolerant, so please, BE CAREFUL)."

2) RAM Overclocking

Now that you've found your maximum CPU speed, you need to find your maximum RAM speed. This is a bit more tricky due to the fact that you can also change the RAM timings. Loser (higher numbers) RAM timings will allow for faster speeds (in MHz, not performance) at the same voltages. Ideally though, you bought DDR2-800 and can run your ram synchronously with your CPU without bottlenecking it. However that is not always the case, especially for those of us with older systems (I have DDR-400). If you can, set the CPU and (Athlon 64 users only) HT Link multiplier fairly low. If your stock multiplier is 11 or 12, set it down to 7 or 8. If it's 7 or 8 stock, well hopefully you can get it down to 6. Another thing you can do is to set the RAM divider to such that the RAM is running way faster than the bus speed. Some boards may even have options for running at over twice the bus speed.

I'm going to take this time to give a quick overview of RAM timings. The most popular of the RAM timings is Cas Latency, or tCL. The following three timings are tRCD, tRP, and tRAS. The other “popular” one is Command Rate, or CR. Most of the time RAM timings are reported in this tCL-tRCD-tRP-tRAS CR. For example, with DDR RAM the “perfect” timings were 2-2-2-5 1T. Just remember these names when you are editing the timings in your BIOS, as they may not be exactly in this order. I've seen where 2-2-5-2 1T would be the same as the conventional 2-2-2-5 1T. If you put something that's normally a 5 as a 2, it's probably not going to like it one bit. Like I said, for DDR RAM, the “golden” timings were 2-2-2-5 1T. This could be easily substituted for timings like 2.5-3-3-8 1T if the RAM could get to 280MHz or more. I would never raise DDR timings above 3-3-3-8 2T for the sake of pure speed, unless the RAM was some crappy stuff that came with 3-4-4-8 2T timings or something.

For current DDR2 RAM (of which I have very little first hand experience), it seems 4-4-4-x 1T is very good, simply because DDR2 RAM can run much faster than DDR. I wouldn't say there are any specific “golden timings” for DDR2, as it greatly varies on how fast the ram is actually going. I've seen as low as 3-3-3-10 at slower (for DDR2) speeds, and as fast as 6-6-6-x for stuff that is either a) really cheap or b) gets to quite high MHz speeds.

For DDR3 RAM, no comment on that as it's nowhere near a mature state. Come back in a year.

Back to actually overclocking your RAM. If timings seem too daunting to you, simply because there is so much that you can do (wrong), then don't mess with them. Yes, this could possibly block you out from getting the most potential out of your system, but it's probably better to be comfortable with what you're doing. The procedure for overclocking your RAM while not your CPU (as much) is roughly the same as the reverse. Take a note of the set voltage, and the voltage read from the BIOS, find the maximum RAM speed that's stable in SuperPi at that particular voltage. Increase voltage by one increment, then find the maximum speed at this voltage. Again, I would expect that the higher you go with voltage, the lower return you see per increase.

Unfortunately, I cannot tell you what voltage is safe for your ram if you have DDR RAM. The range from different types of chips is anywhere from 2.9V all the way to 3.5V. Given that, it would be wise to stay under 3.0V. If you get to this point and you're still not satisfied you can keep increasing the voltage, but unless you KNOW it's safe, I will recommend not doing this. The only way you'll have a realistic ballpark figure is to know what type of RAM it is, and do a search on more overclocking oriented message boards.

For DDR2 RAM, stock Voltage should be 1.8V, and you should be safe anywhere up to 2.1V. I don't know of any specific RAM being able to take more or less than average, so these figures are what you get. If even 2.1V doesn't give you enough speed to match your maximum CPU speed, then you may want to relax (raise the numbers) the timings I talked about earlier just slightly to see what kind of speed increase that affords you.


3) Mixing the Two

Assuming you've gotten this far during your actual trials, you've found your max CPU speed and max RAM speed. You've gotten everything else smoothed out (in theory), all that's left is to is figure out the “sweet spot” that balances the CPU overclock with the RAM overclock. If you have to sacrifice one for the other, sacrifice RAM speed for CPU speed. How well you'll be able to match the maximum speeds will depend on how flexible the RAM dividers are on your motherboard. Keep in mind though, unless you have an Athlon 64, you'll want synchronous timings. This means either RAM speed = bus speed, or RAM speed is set to double the bus speed. Unless you can get a very large boost in pure MHz on the RAM over what this restricts you too, synchronous RAM is happy RAM. Very large, to the tune of over a 50MHz speed increase (before doubling the speed for the DDR(2) rating.)


D) Choice Picks

This section will of course be very volatile as prices fluctuate and new models are introduced. I will make an attempt at keeping this up to date, but again, no promises past the first line.


Recommended Intel CPUs





Recommended AMD CPUs
Keep in mind Phenom processors are coming out in November and December, if the Internet is to be trusted



Recommended Motherboard List
For this section, I will simply refer you to another thread, on another message board.
Core 2 Duo and AM2 motherboard thread at AnandTech forums.


Recommended DDR2 RAM
In theory, I only need to talk about DDR2 RAM. If you're looking for DDR RAM at this point in time, chances are your system is way out of date, However, if you'd rather spend $50 on 1GB of DDR instead of $50 on 2GB of DDR2, that's totally up to you.

DDR2 RAM, this is easy too. In almost every case you can get 2GB of cheap DDR2-800 RAM, it won't bottleneck your system, and you'll get great performance for about $50-60. However, for some more specific suggestions:


However, I would not hesitate to get any DDR2-800 RAM rated at 4-4-4-x for under $65. That will give you plenty of headroom, until you venture into the more extreme side of overclocking.


V. Graphics Cards



<GPU section in progress by Ashex, get on his case about it>


VI. When (Not) to Panic






Thats all folks!

If anyone has anything to add, correct, replace, etc, please do speak up. I will be happy to add to the OP and give credit where it's due.


November 1st Edits:
First edit: Added/Updated RivaTuner to Windows GUI Overclocking utilities, fixed random grammar mistakes, edited Processor entry in “Terms Used”, Nvidia Driver paragraph in “Drivers”, added pictures.

Second edit: Expanded thermal paste guide. Power supplies are coming soon, I swear.

Third edit: Changed wording in “How many rails?” block. Finally added power supply recommendations.

Forth edit: Added ATI Tray Tools, moved (to “Problems?”) and added on to section about resetting the BIOS.

Most recent edit: Added 915/925X section by ChubbyChimp.

November 2nd Edits
Most Recent Edit: Added suggestion for Intel TAT and Core 2 Temperature guide by maninacape.

February 6th Edits
Updated CPU suggestions, fixed CoreTemp link, updated thermalright ultra 120 heatsink suggestion/link

This article is ©2008 by the respective authors. Reproduction is prohibited without express permission from all contributors.

Creator: pik_d :: 931 hits