Friday is here, and the 'A Taste of Science for the Weekend' corner is back — number 75.
This time: quartz and clock frequency, the extraordinary challenges of overclocking, and the connection to helium.
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Forget the climate crisis or world peace. The group of nerds in the video is busy with something far more important — overclocking.
To understand exactly what that means, we first need to understand what a computer's operating frequency is and how it's managed.
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A computer is built on semiconductor transistors that cyclically switch their state between electrically conductive and insulating.
Each switch from conductive to insulating is a clock pulse, and with every pulse the computer executes an operation. The higher the clock rate, the more operations the computer performs.
The clock rate is based on a tiny quartz crystal located on the motherboard.
Quartz has a property called piezoelectricity. If it absorbs a physical shock it converts it into an electrical current, and if it absorbs an electrical current it converts it into mechanical vibrations at a specific frequency.
The quartz crystal is cut to precise dimensions in order to oscillate at the required frequency, and its advantage is that it produces a pure sine wave — an exceptionally regular and accurate signal.
The frequency produced by the quartz undergoes conversion into an electronic frequency.
Since it is too low for the high operating frequencies of modern computers, the frequency is multiplied dozens of times per second using dedicated components.
All computer components operate in harmony according to the same base frequency, but the multiplication factor differs for each component. A CPU, for example, receives a higher operating frequency than a GPU.
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The current frequency ceiling for processors is around 5 GHz.
The reason is that a semiconductor needs to charge electrically to a sufficient degree in order to become conductive, and as the frequency rises the charging time available within each cycle becomes very short — so the voltage must be increased in order to push enough electrons through to turn it conductive before the next pulse.
Raising the voltage causes a rise in temperature, and the processor risks burning out.
The indirect solution is to increase the number of processors operating in parallel, rather than pushing the clock rate of a single processor higher.
Another challenge is that the high electrical voltage is supplied to the processor by voltage converters known as VRMs. A single converter cannot sustain high voltage for extended periods, so multiple converters must be placed on the board, each supplying power in turn for short intervals.
Raising the voltage is only feasible on professional motherboards equipped with a large number of high-quality voltage converters.
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Overclocking is the act of pushing the clock frequency above the recommended ceiling, which risks burning out the processor.
It is possible to increase the base frequency for all computer components, or to increase the frequency multiplier for the CPU alone, while the rest of the computer's components continue to operate normally.
In this experiment, the processor reached a speed of just over 9 GHz, breaking the world record.
Achieving that speed was made possible by an extraordinary cooling medium — liquid helium.
Standard CPU cooling keeps the processor at roughly 30–100 degrees Celsius.
Overclocking experiments typically use liquid nitrogen, which approaches a temperature of minus 200 degrees Celsius.
Helium, by contrast, is a cryogenic liquid — it is liquid only at minus 269 degrees Celsius, very close to absolute zero.
The challenge with such aggressive cooling is that when silicon becomes too cold, its atoms do not contain enough energy to allow electrons to flow through them.
A clock frequency that high is the result of precise scientific engineering.
On one hand, the processor had to be cold enough to survive the high voltage; on the other, warm enough to allow normal electrical current to flow.
The experimental results enable the design of better processors and motherboards, and the electrical behavior of silicon at such temperatures also holds research significance for the field of quantum computing.
Shabbat Shalom 😊
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Video credit: ElmorLabs
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