3. Cooling
Cooling is the process of reducing the temperature of an object or system. Cooling is closely related to CPU speed. The better the cooling provided to the CPU, the lower the temperature that the CPU must handle.
The lower the temperature that the CPU has to handle, the less risk of damage or failure that can occur to the CPU. The less risk of damage or failure that can occur to the CPU, the higher the clock rate that the CPU can achieve. So, cooling has a positive effect on CPU speed.
However, cooling also negatively affects CPU speed. The better the cooling provided to the CPU, the greater the cost to build and run the cooling system.
The greater the cost of building and running a cooling system, the greater the burden that CPU manufacturers and consumers must bear. So, cooling negatively affects CPU speed.
Challenges in Increasing CPU Speed
From the factors affecting CPU speed, it can be seen that there are several challenges faced by engineers and scientists in increasing CPU speed. These challenges include:
1. Physical limits
Physical limits are limitations determined by the laws of physics. The physical limits relating to CPU speed are transistor size, voltage, and heat. The size of the transistor cannot be reduced continuously without causing problems. One problem that can arise is quantum tunneling, which is a phenomenon in which electrons can cross transistors without being hindered by potential obstacles.
Quantum tunnelling can cause transistors to become unstable and unable to function properly. The smallest transistor size that can be made today is about 5 nanometres (mm), and it is estimated that the size of the smallest transistor that can be made in the future is about 1 nm. So, transistor size has a physical limit that cannot be crossed.
The voltage also cannot be increased continuously without causing problems. One problem that can arise is overheating, which is a phenomenon where the CPU temperature becomes too high and exceeds the tolerance limit.
Overheating can cause the CPU to become damaged or shut down. The highest tolerable CPU temperature today is around 100°C, and it is estimated that the highest tolerable CPU temperature in the future will be around 200°C. So, voltage has a physical limit that cannot be crossed.
Heat also cannot be reduced continuously without causing problems. One problem that can arise is a cooling limit, which is a phenomenon where the cooling system cannot lower the CPU temperature lower than the ambient temperature.
Cooling limits can cause the CPU to not operate optimally. The lowest ambient temperature achievable today is about -273°C, and it is estimated that the lowest ambient temperature achievable in the future is around -273°C. So, heat has a physical limit that cannot be crossed.
2. Economic limits
Economic limits are limitations determined by cost and demand. The economic limits related to CPU speed are production costs, operating costs, and consumption costs. Production cost is the amount of money that must be spent to make a CPU. Factors affect production costs, such as transistor size, voltage, and cooling.
The smaller the transistor size, the higher the voltage, and the better the cooling, the higher the production cost. Factors also influenced production costs, such as technology, raw materials, labor, and competition. The more advanced the technology, the scarcer the raw materials, the more expensive the labor, and the fiercer the competition, the higher the production cost.
Operating cost is the amount of money that must be spent to run a CPU. Factors affect operating costs, such as voltage, power, and cooling. The higher the voltage, the greater the power, and the better the cooling, the higher the operating cost. Factors also affected operating costs, such as efficiency, reliability, and safety. The lower the efficiency, the lower the reliability, and the lower the safety, the higher the operating costs.
Consumption cost is the amount of money that must be spent to buy a CPU. Factors influence the cost of consumption, such as production costs, operating costs, and demand. The higher the cost of production, the higher the cost of operation, and the lower the demand, the higher the cost of consumption. Factors also influenced the cost of consumption, such as quality, features, and brand. The lower the quality, the fewer features, and the less well-known the brand, the lower the consumption cost.
Of the three types of cost, it can be seen that there is a trade-off between CPU speed and cost. The higher the CPU speed, the higher the cost. The higher the cost to be incurred, the lower the profit that can be obtained. The lower the profit that can be obtained, the lower the motivation to increase CPU speed. So, costs have an economic limit that cannot be crossed.