overclocking

[ulias]

Extreme Overclocking


Public Service Announcement: Overclock At Your Own Risk

Concerns

When considering any type of overclocking, we like to remind readers that overclocking will void the warranty of your components. While companies promote products that are designed to overclock - such as Intel's Core 2 Extreme processors - any claims that it was designed for modification are accompanied by disclaimers telling you that you will void your warranty if you modify them beyond specifications.

Right on Intel's website you can read this: "Plus, the Intel Core 2 Extreme processor locks (overspeed protection) have been removed so you can mod and overclock your PC beyond the extreme.1" Unlocking the clock multipliers so owners can experiment with overclocking is one selling feature of the processor.

As an intelligent consumer, though, you need to check the fine print. The 24 word comment on cool and exciting adjustable speeds is accompanied by the notation marked by a superscripted 1. That disclaimer has twice as many words and concludes by stating that Intel does not warranty anything pushed beyond spec.
"¹ Altering clock frequency and/or voltage may (i) reduce system stability and useful life of the system and processor; (ii) cause the processor and other system components to fail; (iii) cause reduction in system performance; (iv) cause additional damage; and (v) affect system data integrity. Intel has not tested, and does not warranty the operation of the processor beyond its specifications."
These two statements underscore the two major philosophies at work here. The first is that companies genuinely want to stand behind their products; the second is that there are risks inherent in pushing hardware past its design limitations. These two issues don't mesh well for 99% of the companies out there. If you take a Ginsu knife and abuse it, they will replace it, but when you are talking about delicate semiconductors, replacing a component is a much more expensive proposition.
One main concern with overclocking is the possibility of destroying the components you are going to be stressing. Semiconductor companies have extensive quality assurance measures in place to make sure products leave the factory in good working order. Manufacturers do not want to have their product come back to them under warranty; it cost money to fix or replace defective parts. Maintaining warranties for appropriately used products is required to keep customer confidence high and hopefully result in repeat business. However, companies do not want to replace intentionally altered components.
That said, if we are going to void our warranties, then we should to talk about risks involved and how to minimize them


Overclock At Your Own Risk: Continued

How do components die? The simple answer is use, but the longevity of a semiconductor depends on a few factors. While there are a host of things that can make a semiconductor or other circuitry fail, there are three that affect most common components: electrical current, material purity and temperature. While the manufacturing process for semiconductors generally has stringent quality assurance, not all parts come out exactly the same. Flaws exist, and this is something we all have to understand and live with. While that is out of our control, the other two factors generally are not.
Electromigration

In an article by Thomas "Tom" Pabst, he mentions a phenomenon called electromigration, one of many processes that can lead to the degradation of components. Electromigration occurs as a result of metal atoms being moved via the momentum of electrons. Picture this as a sandblaster where the sand, at high velocity, is eroding the walls of the gun. In the case of electromigration, the electrons are moving the metal atoms away from one another. This can cause a circuit to fail by two means: either the atoms are moved apart breaking the circuit, or they are moved closer, so the circuit touches another causing a short. Either way, it is bad news for the components.
You might be saying, "I thought semiconductors were made of silicon?" Yes they are. The reason microchips are made from silicon is that it has the interesting property of being somewhere between a conductor and a resistor; it can allow electrical currents to pass through it or not, depending on what is done to the silicon during the fabrication process. The silicon can conduct electrical currents if impurities exist, so a process called "doping" is used, where the silicon is bombarded by impurities creating positively and negatively charged areas. This is how electrical gates are formed on the silicon chip.
The interesting fact is that semiconductors do not fail from electromigration, as they do not have enough charge carriers. However, when the silicon is doped above a 1% variation from pure, it can conduct electricity and the issue of electromigration can occur. Additionally, microchips have many layers with metal interconnects which naturally are susceptible.
I bring up the fact that conductive materials migrate inside components because there are two major factors that impact the rate at which this happens. The first has been explained - the amount of current flowing through the circuit - and the second is temperature.
Temperature

In an article about electromigration, Dr. J.R. Lloyd states that "just how much current can be permitted and still maintain reliability as the temperature is changed will depend on whether you have nucleation or growth dominated failure and what the dominant diffusion mechanism is. If we have growth-dominated diffusion and we increase the temperature such that we double the diffusion coefficient (approximately 20 degrees for Al alloys and grain boundary diffusion), we must reduce the current density by half. Conversely, if we want to increase the current density by a factor of two, we must ensure that the temperature is at least 20 degrees cooler. If failure is nucleation dominated, an approximate 30% reduction in current is needed for a similar temperature increase to maintain equal reliability."
In laymen's terms, he is stating that for every 20 degrees Celsius above the ambient test temperature, the current flowing through must be halved. Of course, this is the opposite of what happens while overclocking: not only do we increase the amount of energy passing through the chip (adding to the breakdown effects of electromigration) but we also increase the temperature, since putting more electrical energy through the same circuit heats it. All wires and circuits have to deal with internal resistance. However, interestingly, as temperatures rise, semiconductors conduct better and metals resist more. Therefore, as the flow moves from silicon to metal, the force of the flow will cause the metal to separate, either breaking the circuit or short-circuiting as it comes in contact with another circuit. Due to these and many other factors, adequate cooling is mandatory for overclocking.

[Kingroudy]

http://www.vcoderz.com/forum/showthr...t=overclocking
this is a thread i already opened about this topic
i said earlier that i dont dare to do it, but now, i'd really like to, and not on my own risk for sure
what do u know about this issue guys? share

[Iceberg]

I have clocked my old P3 back at home, years ago.. it still works and faster than most P4 up till 1.5Ghz (My CPU is 600MHz on base). I won't give the details, you just have to get a board that can be clocked and get the exact voltage and frequency specs specific to your board. Also i'd say prepare an RC filter of about 330 ohms and 2.2 nanofarads, the values may have a variance of + or - 15% depending on the board; this filter can be used to clock the processor, it should be soldered somewhere at the back of the board to connect 2 CPU jumpers (again it's processor specific). You need lots of specs, lots of reading, you can try this only once.. if you fail, buy another board and processor.