Processor power dissipation

Designing CPUs that perform tasks efficiently without overheating is a major consideration of nearly all CPU manufacturers to date.

Historically, early CPUs implemented with vacuum tubes consumed power on the order of many kilowatts.

Current CPUs in general-purpose personal computers, such as desktops and laptops, consume power in the order of tens to hundreds of watts.

Some other CPU implementations use very little power; for example, the CPUs in mobile phones often use just a few watts of electricity,[1] while some microcontrollers used in embedded systems may consume only a few milliwatts or even as little as a few microwatts.

Datasheets normally contain the thermal design power (TDP), which is the maximum amount of heat generated by the CPU, which the cooling system in a computer is required to dissipate.

Both Intel and Advanced Micro Devices (AMD) have defined TDP as the maximum heat generation for thermally significant periods, while running worst-case non-synthetic workloads; thus, TDP is not reflecting the actual maximum power of the processor.

Other major uses include fast video cards, which contain graphics processing units, and power supplies.

While energy-saving features have been instituted in personal computers for when they are idle, the overall consumption of today's high-performance CPUs is considerable.

The total amount of leakage currents tends to inflate for increasing temperature and decreasing transistor sizes.

[7] Power consumption can be reduced in several ways,[citation needed] including the following: Historically, processor manufacturers consistently delivered increases in clock rates and instruction-level parallelism, so that single-threaded code executed faster on newer processors with no modification.

[12] More recently, in order to manage CPU power dissipation, processor makers favor multi-core chip designs, thus software needs to be written in a multi-threaded or multi-process manner to take full advantage of such hardware.

Many multi-threaded development paradigms introduce overhead, and will not see a linear increase in speed when compared to the number of processors.