Overclock Intel

What is overclocking?

Overclocking is pushing your CPU to run at a faster clock speed than the manufacturer has it set at.

What is involved?

FSB
For Intel Core 2 Duo’s typically you overclock by simply raising the FSB (front side buss). This speed is set at 266Mhz for the E6xxx-X6800. The FSB is set at 200Mhz for the e4xxx series. Raising the FSB is the only way to overclock your Core 2 Duo, unless it is an engineer sample chip or an X6800+ (Both of these have unlocked multipliers.)

Multiplier
To overclock your Intel Core 2 Duo by using the multiplier, you simply change that number to a higher number than its stock multiplier. For example an engineer sample chip E6300 has a multiplier of 7x, but you can change it to a higher value, say 9x. If you leave the FSB at 266, then 9x266 = 2400Mhz = 2.4Ghz.

PCI-E
When you overclock your CPU by raising the FSB, you not only overclock the CPU, but you also overclock your PCI-E. On most motherboards you can lock your PCI-E to 100Mhz (recommended).

RAM
By overclocking your CPU by upping the FSB, you also cause your RAM to be overclocked. But is that a bad thing? Yes and no. For cheap value RAM you can not overclock your RAM much at all. You would be lucky with 50-100Mhz. By simply changing your RAM/CPU divider you can adjust your RAM speed also. Typically a good stable overclock consists of the RAM and the CPU running at a 1:1 ratio. For example if your CPU’s FSB speed set to 400Mhz and your in a 1:1 ratio, then your RAM will show up as running at 400Mhz in the BIOS. Because it is DDR2 the RAM is actually running at 800Mhz effective, which is PC6400 stock speeds.

Socket 775 Motherboards usually support different types of DDR2 Memory. Motherboards natively support 533Mhz DDR2 all the way up to 800Mhz DDR2. It is possibly to run faster memory like DDR2-1000 and even higher like 1200Mhz, but this is only possibly by changing the CPU/RAM divider or overclocking the CPU via FSB.

When looking at RAM, and the speed of the RAM there are two things to take into account. What is the rated speed of the RAM? DDR2 memory typically ranges from 533Mhz to upwards of 1200Mhz. The memory frequency is not the only thing to look at when comparing the speed of RAM. The timings or latencies are also important.

Most value RAM has very “loose” latencies. 5-5-5-15 is quite common for value RAM. Mid end RAM is usually somewhere around 4-4-4-12. Mid-High end RAM has timings like 4-4-3-5 or 4-4-3-8. High end RAM will have low latencies like 3-4-3-9. The most important number is the first number. The lower the first digit the faster the memory.

By default, most motherboards will set the RAM timings to 5-5-5-15, so it is necessary to go into the BIOS and change these timings to the timings recommended by the manufacturer.

Loosening up your RAM timings will allow for a higher overclock. For example if your memory is rated at 4-4-4-12 and is PC6400 and runs at 800Mhz, then “loosening” the timings to 5-5-5-15, might allow for an overclock of upwards of 900Mhz. While at the stock 4-4-4-12, 850Mhz was achievable.

On some motherboards, like my Gigabyte DS3P, all the memory latencies and voltages are locked by default. To view these advanced settings in your BIOS, I pressed Ctrol+F1. This unlocked a hidden menu with advanced features.

NB (North Bridge) Straps
The northbridge has a series of straps. As you overclock, and the FSB increases the NB strap occasionally will change. What changes in the NB is the NB’s latencies. If you ever hit a wall and can not even overclock 1Mhz more then it quite possibly could be your NB strap. To get around this you could try a large jump of 10 or maybe even 20Mhz and see if your PC posts. If you are able to run your CPU and NB at a high strap with tighter timings, it is often times faster then running your CPU at a slightly higher clock. For example depending on the CPU, FSB, and multiplier a Core 2 Duo overclocked to 2.8Ghz may be faster than a CPU overclocked to 2.9Ghz. The NB strap idea is fairly new, and there isn’t all that much information out there.

Vcore (CPU voltage)

The CPU voltage is commonly referred to as “vcore.” The stock voltage for the Intel Core 2 Duo chips is 1.325v. When overclocking, almost always the voltage needs to be increased. But don’t increase the voltage unless you need to.

If you hit a wall and you can’t overclock any further then up the voltage a bit. I usually up it by my vcore by .025v. Once I reach an overclock that I am satisfied with, I will lower the voltage by as little as possible, until Orthos fails. This way I can figure out the lowest vcore required to run my CPU at the speed it is at.

The more volts you put through your CPU, the more heat it is going to create and the more watts it is going to consume.

It is not recommended to exceed 1.5v on air cooling, simply because temperatures are usually far too high. If your overclocking on water cooling or better cooling then 1.5v or a bit higher is nothing to be afraid of, as long as the temperatures are good.

Fans, heatsinks and thermal compound.

It is not recommended to overclock very much on the retail heatsink provided by Intel. It is a relatively small heatsink and will not handle large amounts of heat generated by a high OC.

It is recommended to overclock using an aftermarket heatsink. Some good ones include: the Tuniq Tower 120, Big Typhoon, Artic Freezer 7 PRO, Thermaltake Ultra -90, Zalaman 9700. Larger heatsinks have a larger surface area, and thus disperse heat a lot better than smaller ones.

To improve temperatures for any heatsink you can do a couple of things. First, be sure and use some good, high quality thermal compound such as Artic Silver 5. Second, you can lap your heatsink. Lapping is the process of sanding down your heatsinks surface. This gets rid of some of the small machine marks and tiny pits in the heatsink. Lapping is done by using different grits of sand paper – 400 all the way up to 2000 or higher. Lapping is not very hard but takes a lot of time and patience. Lapping a heatsink will typically yield performance gains ~2-8C.

Monitoring temperatures

There is a handful of software out there that will allow you to monitor the temps of your CPU. Probably the most trusted program is called TAT (Thermal Analysis Tool) and can be downloaded directly from Intel. It usually gives accurate readings for most Core 2 Duo CPU’s. It measures the temperature of both CPU cores and this data can be monitored by TAT.

Intel recommends that the temperature of both CPU cores does not exceed 60C. The general rule of thumb I follow however is I like to stay under 65C max load, because I know in every day applications I will never even come close to reaching 60C. Gaming, encoding and other tasks never fully max out both CPU cores at 100% full load like Orthos does.

Software needed:

To safely overclock, you will need some sort of CPU monitoring program. I personally recommend TAT. Other programs such as Gigabytes Easy Tune, can be terribly off. I had Easy tune at one time reporting negative temps, while on air cooling. :p

The second program you will need is Orthos. Orthos is a program designed to torture your CPU and put it under the most extreme conditions. It tests stability and halts and lets you know when an error has been detected. Orthos is a mod of Prime95. The earlier versions of Prime95 would not stress a core2duo CPU, because it was designed for single core processors. Orthos is a mod that basically runs two instances of Prime95 in one window.

Another piece of software that I’d recommend is Super Pi. Super pi is a small CPU benchmarking program. It doesn’t put nearly as much stress on your CPU as Orthos, but is a good program for monitoring increases in performance. Super pi calculates Pi – 3.14159… from 64k all the way up to 32M or 32 Million digits. Usually pi is calculated to 1 or 2 million digits for benchmarking purposes.

Another program that is not required but is recommended is memtest86. Memtest86 is a program that puts stress on your memory and will scan it for errors. If you are ever going to be overclocking your memory or playing with the memory timings, this program is highly recommended.

The following software can be downloaded from: http://www.asusreviews.com/Download.html

Lets Get started!

The first step is to enter your BIOS. To do this, boot up your computer and while it begins to post hit the Delete key.

There are two main ways people go about overclocking. The first way is by increasing your FSB by 10mhz at a time and running Orthos and monitory temps, and increasing voltage when needed.

The second way is to just jump into a moderate overclock. This is my favorite way, especially with the Core 2 Duo line and all of its potential. When I overclocked my e4300, I immediately overclocked from 2.4Ghz from the stock 1.8Ghz. I did this by upping my FSB to 266. I then ran Orthos and continued to overclock the FSB 10-20Mhz at a time until I hit a problem. Once I got an error or could not post, I’d add some vcore to the CPU. Then would boot up and run Orthos again.

When trying to figure out your CPU’s max overclock, set your memory to a 1:1 ratio. That way you are not putting unnecessary stress on your RAM. Once you figure on your CPU’s max overclock then play around with the memory/cpu ratio and tighten up your timings if needed.

What kind of overclock can I expect for my Core 2 Duo?

On high end air cooling, and the right RAM and a good overclocking motherboard, you should expect something around the following:
E4300 – 2.8-3.2Ghz

E6300 – 2.8-3.4Ghz

E6400 – 3-3.6Ghz

E6600 – 3.2-3.8Ghz

E6700 – 3.3-3.8Ghz

X6800 – 3.4-3.9Ghz

Technorati Profile

What Is Overclocking?

Introduction

Many people probably don't know what overclocking is but have possibly heard the term used before. To put it in its simplest terms, overclocking is taking a computer component such as a processor and running at a specification higher than rated by the manufacturer. Every part produced by companies such as Intel and AMD are rated for a specific speeds. They have tested the capabilities of the part and certified it for that given speed. Of course, most parts are underrated for increased reliability. Overclocking a part simply takes advantage of the remaining potential out of a computer part that the manufacturer is unwilling to certify the part for but it is capable of.

Why Overclock a Computer?

The primary benefit of overclocking is additional computer performance without the increased cost. Most individuals who overclock their system either want to try and produce the fastest desktop system possible or to extend their computer power on a limited budget. In some cases, individuals are able to boost their system performance 25% or more! For example, a person may buy something like an AMD 2500+ and through careful overclocking end up with a processor that runs at the equivalent processing power as a AMD 3000+, but at a greatly reduced cost.

There are drawbacks to overclocking a computer system. The biggest drawback to overclocking a computer part is that you are voiding any warranty provided by the manufacturer because it is not running within its rated specification. Overclocked parts that are pushed to their limits also tend to have a reduced functional lifespan or even worse, if improperly done, can be destroyed completely. For that reason, all overclocking guides on the net will have a disclaimer warning individuals of these facts before telling you the steps to overclocking.

Bus Speeds and Multipliers

To first understand overclocking a CPU in a computer, it is important to know how the speed of the processor it computed. All processor speeds are based upon two distinct factors, bus speed and multiplier.

The bus speed is the core clock cycle rate that the processor communicates with items such as the memory and the chipset. It is commonly rated in the MHz rating scale referring to the number of cycles per second that it runs at. The problem is the bus term is used frequently for different aspects of the computer and will likely be lower than the user expects. For example, an AMD XP 3200+ processor uses a 400 MHz DDR memory, but the processor is in fact using a 200MHz frontside bus that is clock doubled to use 400 MHz DDR memory. Similarly, the new Pentium 4 C processors have an 800 MHz frontside bus, but it is really a quad pumped 200 MHz bus.

The multiplier is the multiple that the processor will run at compared to the bus speed. This is the actual number of processing cycles it will run at in a single clock cycle of the bus speed. So, a Pentium 4 2.4GHz "B" processor is based on the following:

133 MHz x 18 multiplier = 2394MHz or 2.4 GHz

When overclocking a processor, these are the two factors that can be used to influence the performance. Increasing the bus speed will have the greatest impact as it increases factors such as memory speed (if the memory runs synchronously) as well as the processor speed. The multiplier has a lower impact than the bus speed, but can be more difficult to adjust.

Let's look at an example of three AMD processors:

CPU Model	Multiplier	Bus Speed	CPU Clock Speed
Athlon XP 2500+	11x	166 MHz	1.83 GHz
Athlon XP 2800+	12.5x	166 MHz	2.08 GHz
Athlon XP 3000+	13x	166 MHz	2.17 GHz
Athlon XP 3200+	11x	200 MHz	2.20 GHz

Let's then look at two examples of overclocking the XP2500+ processor to see what the rated clock speed would be by changing either the bus speed or the muliplier:

CPU Model	Overclock Factor	Multiplier	Bus Speed	CPU Clock
Athlon XP 2500+	Bus Increase	11x	(166 + 34) MHz	2.20 GHz
Athlon XP 2500 +	Multiplier Increase	(11+2)x	166 MHz	2.17 GHz

In the above example, we have done two changes each with a result that places it at either the speed of the 3200+ or a 3000+ processor. Of course, these speeds are not necessarily possible on every Athlon XP 2500+. In addition, there may be a large number of other factors to take into consideration to reach such speeds.

Because overclocking was becoming a problem from some unscrupulous dealers who were overclocking lower rated processors and selling them as higher priced processors, the manufacturers started to implement hardware locks to make overclocking more difficult. The most common method is through clock locking. The manufacturers modify traces on the chips to run only at a specific multiplier. This can still be defeated through modification of the processor, but it is much more difficult.

Voltages

Every computer part is regulated to specific voltages for their operation. During the process of overclocking the parts, its possible that the electrical signal will be degraded as it traverses the circuitry. If the degradation is enough, it can cause the system to become unstable. When overclocking the bus or multiplier speeds, the signals are more likely to get interference. To combat this, one can increase the voltages to the CPU core, memory or AGP bus.

There are limits to the amount of additional voltage that can be applied to the processor. If too much voltage is applied, the circuits inside the parts can be destroyed. Typically this is not a problem because most motherboards restrict the possible voltage settings. The more common problem is overheating. The more voltage supplied, the higher the thermal output of the processor.

HEAT!

The biggest obstacle to overclocking the computer system is heat. Today's high-speed computer systems already produce a large amount of heat. Overclocking a computer system just compounds these problems. As a result, anyone planning to overclock their computer system should be very aware of the needs for high performance cooling solutions.

The most common form of cooling a computer system is through standard air cooling. This comes in the form of CPU heatsinks and fans, heat spreaders on memory, fans on video cards and case fans. Proper airflow and good conducting metals are key to the performance of air cooling. Large copper heatsinks tend to perform better and the greater number of case fans to pull in air into the system also helps to improve cooling.

Beyond air cooling there is liquid cooling and phase change cooling. These systems are far more complex and expensive than standard PC cooling solutions, but they offer a higher performance at heat dissipation and generally lower noise. Well-built systems can allow the overclocker to really push the performance of their hardware to its limits, but the cost can end up being more expensive than processor to begin with. The other drawback is liquids running through the system that can risk electrical shorts damaging or destroying the equipment.

Component Considerations

Throughout this article we have discussed what it means to overclock a system, but there are a lot of factors that will affect whether a computer system can even be overclocked. The first and foremost is a motherboard and chipset that has a BIOS that allows the user to modify the settings. Without this capability, it is not possible to modify the bus speeds or multipliers to push the performance. Most commercially available computer systems from the major manufacturers do not have this capability. This is why most people interested in overclocking tend to buy specific parts and build their own systems or from integrators who sell the parts that make it possible to overclock.

Beyond the motherboards ability to adjust the actual settings for the CPU, other components must also be able to handle the increased speeds. Cooling has already been mentioned, but if one plans on overclocking the bus speed and keeping the memory synchronous to offer the best memory performance, it is important to buy memory that is rating or tested for higher speeds. For example, overclocking an Athlon XP 2500+ frontside bus from 166 MHz to 200 MHz requires that the system have memory that is PC3200 or DDR400 rated. This is why companies such as Corsair and OCZ are very popular with overclockers.

The frontside bus speed also regulates the other interfaces in the computer system. The chipset uses a ratio to reduce the frontside bus speed to run at the speeds of the interfaces. The three major desktop interfaces are AGP (66 MHz), PCI (33 MHz) and ISA (16 MHz). When the frontside bus is adjusted, these buses will also be running outside of specification unless the chipset BIOS allows for the ratio to be adjusted down. So it is important to know how adjusting the bus speed can impact stability through the other components. Of course, increasing these bus systems can also improve performance of them, but only if the components can handle the speeds. Most expansion cards are very limited in their tolerances though.

Slow and Steady

Now those who are looking to actually do some overclocking should be warned not to push things too far right away. Overclocking is a very tricky process of trial and error. Sure a CPU may be able to be greatly overclocked in the first try, but it is generally better to start out slow and gradually work the speeds up. It is best to test the system fully in a taxing application for an extended period of time to ensure the system is stable at that speed. This process is repeated until the system does not test fully stable. At that point, step things back a bit to give some headroom to allow for a stable system that has less chance of damage to the components.

Conclusions

Overclocking is a method for increasing performance of standard computer components to their potential speeds beyond the rated specifications of the manufacturer. The performance gains that can be obtained through overclocking are substantial, but a lot of consideration must be done before taking the steps to overclocking a system. It is important to know the risks involved, the steps that must be done to obtain the results and a clear understanding that results will very greatly. Those who are willing to take the risks can get some great performance from systems and components that can end up being far less expensive than a top of the line system.

For those who want to do overclocking, it is highly recommended to do searches on the Internet for information. Researching your components and the steps involved are very important to being successful.