i7 Overclocking for Beginners

[nightkhaos]

IMPORTANT: This guide is only for Bloomfield, i.e. LGA1366, based i7s. For Lynnfield, i.e., LGA1156, based i7s or i5s you can use this guide, but be warned that the procedure may be slightly different due to the different hardware. Alternatively you can wait until I write my dedicated i5 overclocking guide when I get some i5 hardware to experiment with.

Hi everybody,

After Overclocking my i7 920 D0 to 3.8 GHz I thought I would start a guide on how to overclock the i7 920 D0. This will involve lots of use of the "Edit" function, and please if anything is wrong or want to add anything to this please don't hestiate to post a reply. Consider this a work in progress.

If anyone has any experience with other i7 revisions and feel that the process is so different as to justify a new section please reply.

Nightkhaos

Jargon File
There are a few concepts you will need to understand for overclocking, here I list them and explain what they are:

• BCLK or Base Clock is the Base clock the motherboard runs at. This is defined by the model of CPU, and by default is set to 133 MHz for the i7 920 D0, for a total speed of 2.66 GHz.
• CPU Multiplier: This is a function of SpeedStep, the Intel technology that underclocks your CPU when it is under low load. In order to change the current frequency that the CPU is running at the computer will change the multiplier. The multiplier with run at 20 for the i7 920 D0 when the CPU is running at full speed.
• Intel TubroBoost this function gives an extra boost of speed to the processor, by changing the maximum multiplier from 20 to 21.
• Vcore voltage: this is the voltage which the motherboard supplies to the CPU rails. You will need to adjust this if the CPU is taking to much power to maintain destinct logic levels. (i.e. it will become unstable)
• DRAM voltage: this is the voltage suppiled by the motherboard to the DDR3 RAM.
• RAM Multiplier: this is the muiltiper of the RAM from the baseclock.
• Memory Timings: without defining these your RAM will run at stock or some artibratory value defined by the motherboard. You will need to adjust them to match the specifications given to on your RAM, for example my RAM, Patorit Viper CL8, has times of 8-8-8-24.
• PCIe clock. This should be set manually to ensure that the graphics cards and other PCIe devices function normally. It is the clock at which the PCIe slot operates under.

The Theory
The theory behind overclocking is rather simple. You increase the base clock and multiplier until the speed of your CPU is running at the desired point.

The are a few things to consider however, the RAM is affected by the base clock as well, so you must make sure it is running as close its designed timings, frequency and voltage. You computer will also have trouble under load if there is not enough voltage, so you will need to increase the voltage to Vcore if you cannot get the machine stable.

Thermal output: an aftermarket cooler is a must when overclocking because the stock cooler that comes with the CPU is not only loud, it is not very efficent. Your cooler, be it water or air, will determine how much you can overclock your CPU. The better your cooler, the more you can push your chip, because the temperatures will be lower. I will explain this more in detail later.

Software
In order to begin it is recommend you have the latest drivers. What we require is a stress testing application. I generally use OCCT, but there are other applications, all which have their advantages and disadvantages. I like OCCT because of it's ease of use, and the wealth of information it provides.

I also run CoreTemp so that I do not have to have my moniter on to check the status of the temperatures (I have a G15, which CoreTemp supports).

My friends and I have developed a full proof testing method, and we call it POST, Boot, Prime, or PBP. There are three stages of stablity:

1. POST - The computer boots but is unable to start an operating system.
2. Boot - The computer is able to get into the operating system
3. Prime - the computer can run fully loaded on 8 threads (for an i7) for an extended period of time.

The goal is to get Prime stable, because that means your computer will not be pushed to breaking point. My friend once got his system boot stable so that he could run GTA IV on a Core 2 Duo. He was able to play for about two hours then he would need to turn his computer off for about an hour or leave it idle to let it cool down!

Hardware
Your motherboard is key to any overclocking operation. It needs to be robust enough to handle the abuse, and configurable enough to allow you to overclock the system. I personally recommend the Gigabyte X58-UD5, but also worth considering are the ASUS Rampage II Deluxe, and the ASUS P6T Deluxe V2. Even a ASUS Rampage Gene will work well, if you're pushed for space. All I can really say is shop around, read reviews, and find one that best suits your needs.

Secondary, but just as important, is the processor. The i7 920 D0 is recommended at the moment because it is the cheapest of the i7 range, and handles well over a wide temperature range. However it is reaching it's EOL, so when this happens we will need to find another i7 to work with.

Then there is your RAM. I recommend you get CL7 or CL8 RAM at around or above 1600MHz. From the information I have read there is a little point getting faster RAM, however there is no harm in it, apart from to your bank balance.

Cooling
Keeping your CPU and RAM cool is the most important factor. The RAM, if set to stock, the manufacturer's defined times, shouldn't need active cooling, however the CPU will.

If you can afford it you can go watercooling. The advantage to this is due the mechanics of a watercooling loop it is possible to cool the CPU to a level lower than the ambient tempeture of the case.

Air on the other cannot get the tempeature any cooler than ambeint. This is especially important if you live in a hot country or use your computer in a hot boiler room.

If the CPU gets too hot, it will ceese to function properly, and will trigger a thermal tilt-bit, which will immediately shut down your computer, or worse, the chip will melt and become permanently damaged.

I will not give you suggests for cooling as this comes down to personal preferance, budget, and sometimes the clearance provided by the case.

Don't be afarid to ask questions when it comes to cooling. For example in order to fit my heatsink in my case I needed to remove the 220mm fan from the case, and it still functions prefectly.

Procedure
Right now we have the preparation underway, I will assume you have a working system with the desired cooling and components. I will also assume you have installed an appropriate version of Windows, and OCCT.

Please understand that as I go through the BIOS you may find your BIOS is slightly different.

First off there is a we bit of maths. To start, get the timing and recommend frequency settings for your RAM. Say you bought Patriot Viper CL8 RAM , as I did, then your documentation would say your times are 8-8-8-24 and the RAM runs at 1600MHz.



Now RAM is quite confusing in that lower the numbers means lower latency, but for stability and speed you actually want that number to be higher, i.e. higher latency. Not to high however, as then your cannot do enough operations. To fast, and your RAM may become unstable at high clocks, to slow, and your RAM will take to long to do memory operations. I find the best balance to be CL8 RAM.

The price is usually a good indicator of which RAM is better, but only if you stick to the same brand. And remember, this is only a rule of thumb.

Some RAM has a feature called Extreme Memory Profile (XMP), that automatically sets the RAM to the relevant latency and speed. Now you may be thinking "that's great why don't we just use that?" Well to understand this we must first understand multipliers and the base clock.

Your computer has a base clock, which both the RAM and CPU's clocks are driven off. In order to get that final number, i.e. 1600MHz RAM or 2.66GHz (2660MHz) the modules have a multiplier, which multiplies that clock by a given factor.

As I said earlier, by default the maximum multiplier is set to 20, for the Core i7 920 D0, and the base clock runs at 133MHz. This results in a speed of 2660MHz.

Now the RAM applies the same method. To get 1600MHz for the RAM a multiplier of 12 is applied, resulting in 1596MHz.

Now in order to overclock, we will be increasing the base clock. This means, if XMP was enabled, and the multiplier of 12 continued to be applied when you set the base clock to 200MHz, then the RAM would be running at 2400MHz, which could be damaging the the module. For this reason, to be on the safe side and ensure that the modules don't get damaged, we will manually define the memory timings and multiplier.

There is another danger related to RAM, and that is voltage. Please make sure you set the DRAM voltage manually as well as you could damage the module if you leave it on automatic.

So now, it is time to plan your set a goal for your overclock. Bare in mind that your cooling plays a very important factor. You cannot get 4.0GHz on every cooling system. I would start at a figure you know is obtainable, say 3.0GHz, and work up from there until you find a temperature range you are happy with.

At the moment you have your RAM speed, and desired clock speed. Let us assume you have 1600MHz RAM and want to achieve 3GHz. What you want to do is take your desired CPU clock and divide it by 20 (or the multipler for your relevent CPU), the maximum multiplier:

3000 / 20 = 150

So this will be your base clock. Now then, we need to work out the required multiplier for your RAM. The multiplier unfortunately has to be an integer, so you will either have to get a multiplier of 10, and run your RAM at 1500MHz or a multiplier of 11 and run it at 1650. Some motherboards, like mine, only support even integers, further restricting your ability.

So that's the math, let's get in there and do it shall we?

[nightkhaos]

Entering the BIOS
Most X58 boards I have worked with require you to press Delete on the keyboard while the system POSTs in order to access the BIOS.

Depending on your hardware it may take a minute to bring up the BIOS screen. Once this happens you should be greeted with a screen like the one below (click to enlarge).



Please excuse the image. Unfortunately it is not possible to post a screenshot from within BIOS. I had to make do with a makeshift tripod (read, pile of books) and careful alignment of the camera.

In my BIOS we continue into the MB Intelligent Tweaker (MIT) in order to change the settings, which looks something like below (click to enlarge).



For my set-up I have chosen the following:

3.8 GHz with a multiplier of 19 to allow exactly 1600MHz with a multiplier of 8 for the RAM, which means a base clock of 200 MHz.

Depending on what you have decided on your will go through a different procedure.

First, go into Advanced CPU Features. Now the first thing we want to do is disable TurboBoost. This is because TurboBoost does not play that well with overclocking most of the time and all it does is changes the maximum multiplier to your CPUs multipler + 1. Some motherboards, like the Asus P6T Deluxe, implement Turbo via charging your multipler directly (i.e. you set it to 21 instead of 20 for the i7 920 D0), and with the particular board it is safe to leave Turbo on. See below (click to enlarge).



Now then, while you're in here you can also change the multiplier if you have opted to do so. See below (click to enlarge).



Next, press the Esc key to return to the top menu, and scroll down to Base Clock(BCLK) Control and then modify the BCLK Frequency (MHz) to the desired value. See below (click to enlarge).





Now go into Advanced Clock Control and modify the value for the PCIe clock. This is to ensure that it is running at the correct value following all the other changes we have made. You should change this value to 100MHz. See below (click to enlarge).



Go back into the MIT menu and then make sure Extreme Memory Profile(X.M.P.) is disabled and change DRAM Timing Selectable (SPD) to Manual. Then using the settings provided for your RAM set the CAS, tRCD, tRP, tRAS and Command Rate. If you haven't been given a Command Rate it is usually safe to set it to 2. Remember you need to set it for all channels and set it the same for all channels for maximum efficiency. See below (click to enlarge).



As you can see I have set mine to 8-8-8-24 with a command rate of 2.

Next you will set the memory multiplier. I have done this through Advanced DRAM Features but you can change it on the MIT screen as well if you chose. See below (click to enlarge).



Finally there are the Vcore and DRAM Voltages. I also recommend you enable Load-Line Calibration as it reduces Vdroop (the drop in the Vcore voltage under load), however it is not required. See below (click to enlarge).



First, set your DRAM voltage to as close to, but not exceeding, the voltage recommend to you in the documentation for the RAM. For my RAM this was 1.65 Volts. My machine also warned me by highlighting in red when I was going over this limit because going over this limit is likely to damage the memory contorller on my i7, see below (click to enlarge).



Ideally you want to set the voltage of Vcore as low as possible. Start a 1.20 volts, and if the stability testing stages fail, you will need to come back and increase the voltage. I have mine running at 1.25 volts.

Now you are ready to commit the changes and try booting in. Press F10 to save your changes and restart the system.

[nightkhaos]

POST, Boot, Prime
Now that you have committed the changes your computer will commit them and now attempt to boot the system. If all goes well you should see the system POSTing , and Windows will begin to boot, such as below (click to enlarge).



This is the first stage. If this stage fails it can be for one of two reasons, lack of Vcore voltage, or the CPU running too hot.

The second stage is logging into Windows. Again, if your computer fails to do this it is because of one of two reasons.

I will explain how to address these problems later on in the troubleshooting/FAQ section. But first, the stability tests.

Start up OCCT. You should be greeted with something similar to the following.



Monitor to the temperatures for a few minutes. What you are looking for is temperature creep. You should also make sure the figures are reasonable. Anything below 45 degrees when idle should be good enough.

To explain, your cooling equipment is capable of dissipating heat, however if your processor is producing more heat than your equipment can dissipate, there will be a build up of heat, resulting in a slow, consistent rise in temperature.

When you are confident that the temperature is not creeping, now it is time to place a load test.

Set the test time to Infinite, and change the Test Mode to Large Data Set, then press the ON button.

Ideally you should keep this running for about six hours to ensure that the system is stable, but you will get a good idea within the first few minutes of how the system will behave. Please check your power settings don't tell the computer to turn off after a certain period otherwise your computer will turn itself off before it can complete the tests.

When you press the OFF button to signify that you have completed the operation you will be presented with various graphs. See below, click to enlarge.

You CPU should only run at about 80-85 degrees maximum. If you CPU is running hotter than this your risk it becoming thermally understable. Remember, there is an automatic cut off if the CPU achieves over 100 degrees. I recommend watching the CPU temps for the first hour or so and if it goes over 90, STOP.





There ya go, that's it, you have completed the overclocking operation. Now it is unlikely to be clean sailing all the way, so below you will find out troubleshooting pointers.

Troubleshooting/FAQ

My computer doesn't POST or boot into Windows, why is this?

Provided you have set your memory timings correct, there are two likely culprits, cooling or Vcore voltage. Unfortunately it is quite hard to tell between the two without sticking a temperature probe on the CPU yourself. The best thing to do will be raise the Vcore voltage to see if that fixes the issue. In most cases this will be the problem as thermal issues, particularly if you have a modest overclock, should surface when your system is at stock.

When starting the load tests on OCCT, it starts the tests and then suddenly will have a Blue Screen of Death (BSOD), but my temperatures are reasonable when idle, why is this?

This is a classic case of having Vcore set to low. Notice on the graph above how it starts around 1.2 volts and then drops to 1.17 when load begins to be applied? This is because as the CPU gets loaded more, it uses more energy, so you will have a slight voltage drop. Simply increase the Vcore voltage and that should fix the issue.

When starting the load tests on OCCT, it will run perfectly well for about two of three hours and then suddenly fail with a BSOD, why is this?

This is a classic case of temperature creep. Before going off and buying a new cooler, I recommend checking that the heatsink or water block is properly set against the CPU, and that it is conducting properly. Temperature creep is an annoying problem is that your system can appear stable for long periods of time, and then suddenly fail. If your system continues to persist on this behaviour, reduce your overclock slightly or improve your cooling equipment.

Improving your cooling need not cost a lot of money. There are some methods you can try, replacing the thermal compound, lapping the CPU or block, replacing the fan on the cooler with a better one. All which can be done for less than £20.

Why do we overclock? Intel surely tested these CPUs and worked out their maximum performance?

Yes they did, however they set it to a safe level to ensure that no one would have any problems with the CPU. The reason is that every batch, and even different CPUs within the same batch, may perform slightly differently depending on circumstances. You cannot be assured that you can get 4.0GHz out of every chip. And there is a certain kudos that comes with having an overclocked system.

My friend has pretty much the same setup as me, and has managed to overclock his system to X GHz, but when I replicate his setup my computer won't remain stable, why is this?

The environment, and even the equipment itself, will have slight differences that mean you cannot get the same performance out of every chip. The chips were not built with this in mind, so do not expect them to behave exactly the same when overclocked.

Won't this reduce the usable life of the CPU?

In short yes. But first let us consider this, if you are overclocking your system you are most likely trying to get the maximum performance possible out of your CPU for your games. This means that you want to be able to run the latest games, and you will likely replace your CPU in the next 5 years.

Overclocking means you can put that replacement off another one or two years. And even through your CPU, which in theory should run pretty much the same for the next 10 to 20 years, will have it's usable life reduced to say 7 to 15 years, you will find that in the long run you will save money as you do not need to replace hardware as often.

I have been recommended another stress testing/temperature monitering application, what should I do?
OCCT is not the best at stress testing and temperature monitoring, but is the easiest to use in my opinion, and it does do what it's supposed to do, that is help you overclock, very well. But you want to push your system to the limit you are better off using a temperature monitoring application like CoreTemp or Everest and a stress tester like Linpack (or LinX), or even manually starting 8 threads worth of Prime95. It is also important to note that OCCT also has a Linpack testing mode, which as I understand it runs the same tests as Intel's Linpack.

[nightkhaos]

I think I am done, but if there is something I have missed or I didn't explain very well don't hesitate to tell me in a reply or personal message.

[Phage]

[SIZE="1"] 220mm fan .[/i]

Typo ? Otherwise very good guide so far !

[nightkhaos]

Typo ? Otherwise very good guide so far !

Nope. My case came with a 22cm side intake fan. 'Twas a frelling huge fan. But I have worded it more clearly.

[Phage]

A 22cm Fan ?!.....

[nightkhaos]

A 22cm Fan ?!.....

Yep, see? It's really a 23cm fan, but it's an odd shape, and the actual blades are 22 cm. Now...

[Zak33]

A 22cm Fan ?!.....

it's actually officially 23cm.

The Cosmos is famous for it... you could put in onto a Blackhawk, but a Blackhawk wouldn't have enough power to turn it
http://www.coolermaster.com/products...detail&id=3947

[Zak33]

Agent has added some "spare" posts for you kaos.. so you can carry on with your excellent stuff and add more

[nightkhaos]

Right so got a bit done tonight. Managed to get up to the stability tests, but I better call it a night.

[simonw]

Other guides I've seen are confusing, too much technical jargon, etc. This is the clearest one I've seen yet. Excellent work.

[AD-15]

Agreed. This is a fantastic guide, thank you very much for your efforts!

[nightkhaos]

Right, I think that is all. Please, advice, suggestions, comments!

[Agent]

I've found Intels own Linpack (or LinX if you like a GUI ) test much better than OCCT. It seems to show failures quicker, and shows failures even when OCCT and Prime hasn't. Not to mention it seems to get the CPU hotter by a few deg

Worth considering

[Zak33]

quality tbh.. quality