You would probably expect that the clock would be the part of the computer that keeps track of the date and time. While there IS such a date/time clock on the mainboard, the date/time clock is actually driven by the primary oscillator clock built into the mainboard.

This primer deals strictly with the crystal oscillator clock built into the mainboard. The oscillator clock is the main driver for the entire system. Logic gates are built out of semi-conductors. Semi-conductors will block current at lower voltages and conduct current at higher voltages. When voltage from an input and the clock reach a gate at the same time, the conductivity threshold is overcome and the logic gate opens and produces a specific output, which is passed to the next gate. Thus, as the oscillator clock turns on and off, it literally drives a signal through the computer system and triggering rapid calculations.

Clearly, the rate at which the clock oscillates controls how fast the system operates, but in modern computer systems a second oscillator is added (called a multiplier) which increases the effective number of oscillations per second.

Producing the Oscillation

An oscillator uses the resonance frequency of a piece of quartz crystal to create the oscillation in voltage. When a piece of quartz (silicon dioxide) is subjected to a current with a frequency that matches the quartz's resonance frequency, it begins to vibrate. As the quartz crystal vibrates, it temporarilly changes from a non-conducting state, to a conducting state. This oscillation generates a sine wave signal that alternates between the electrically 'on' and 'off' values at fixed intervals based on the resonance frequency of the quartz crystal chosen for the oscillator. To the computer, 'on' equals 1, and 'off' equals 0 (zero). The number of times the oscillator clock changes from zero to one per second is measured in hertz. The system oscillator clock determines just how fast your CPU, RAM and cards run. The faster the clock setting the faster the devices run. Todays oscillator clocks alternate millions of times per second and are rated in 'megahertz'. The oscillation can be modified by mixing the oscillation of the primary clock with the multiplier oscillator, producing a sine wave with a much higher oscillation rate than the quartz is capable of.


This is the process of setting the aforementioned system clock or the multiplier to higher than recommended settings. For efficiency's sake, most CPU manufacturers make only 1 chip design and 'certify' it to run at a certain speed. All chips, regardless of speed are architecturally identical, so there's really no reason why a chip rated at say, 1 gigahertz can't run at 1.1 gigahertz. Overclocking is possible because manufacturers rate the chip lower than they tested it at so as to guarantee stability and reliability. The problem with overclocking is that it produces extra heat. The faster a chip runs, the hotter it gets. This is because there is voltage flowing through it more frequently. When electricity flows through something solid (like the semi-conductors inside the chip) it encounters what is called 'resistence'. The resistence is essentially friction at the atomic level caused by electron exchange that creates heat. The hotter a processor gets, the less effectively it works. If it gets too hot, it burns up and fails, basically frying right there on your board. When this happens, there is often a small puff of blue smoke, thus leading to the old saying of 'the magic blue smoke escaped'.

Overclocking will only gain about 10-15% performance overall and is not usually noticable by the end user. For such a small gain, the risks are fairly large: a burned out processor, a shorted out motherboard or burned memory and peripheral cards.

You should NOT perform 'overclocking' unless you know exactly what you are doing and are willing to pay the price for your mistakes. If you overclock, over-cool the system or expect it all to go up in smoke.

You must approach overclocking with the expectation that your hardware is much more likely to fry. You can't get upset when you overclock your CPU and goes up in smoke. Overclocking frequently requires adjusting clock, multiplier and voltages to get a stable system. Intel, and for a while AMD also, locked their chips in order to prevent overclocking. The chips simply ignore changes made to the mainboard settings that attempt to force the processor to run faster.

InetDaemon doesn't overclock his chips and doesn't recommend that you do so unless you are an electronics engineer. Buying new toys takes money and overclocking is simply too risky to waste the money to get an extra 5-10% performance gain. Besides, twiddling with the BIOS and voltage settings just takes too much time.


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