CPU electrical consumption
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Modern personal computer CPUs (central processing units) consume a considerable amount of electric power. This must be considered when choosing a power supply unit, and when power consumption is constrained by production and cost.
CPUs in other electronics often use far less power. For example, the CPUs in mobile phones or pacemakers use just a few microwatts. CPUs in personal computers use a lot of power because the manufacturers are 'rewarded' (by sales) for raw speed instead of energy efficiency. This top-performance speed requires significantly more power in the cases of most (but not all) CPU architectures. One of the simplest way to reduce the power consumption of a PC's CPU is just to slow its clock rate.
CPUs for desktop computers typically use more power than any other component inside the computer, except perhaps recent technology video cards which are essentially special purpose CPUs (+memory) themselves. The steady trend in CPU power supplies over the past decade has been towards using lower voltages and having considerably higher currents. While energy-saving features have been instituted in PCs for when they are idle, the overall consumption of today's high-drain CPUs is considerable. This is in strong contrast with the much lower energy consumption of CPUs designed for low-power environments. One such CPU, the Intel XScale, can run at 600 MHz with only half a watt of power, whereas x86 PC processors from Intel in the same performance bracket consume roughly eighty times as much energy.
Processor manufacturers usually release two power consumption numbers for a CPU, the typical thermal power, which is measured under normal load, and the maximum thermal power, which is measured under a worst-case set of instructions. For example, the Pentium 4 2.8GHz has 68.4W typical thermal power and 85W maximum thermal power. When the CPU is idle, it will draw far less than the typical thermal power.
There are some engineering reasons for this pattern.
- Performing at higher speed always requires higher power. Reducing processor speed when possible saves power.
- New features generally require more transistors, each of which uses power. Turning unused areas off saves power.
- As a processor model's design matures, smaller transistors, lower-voltage structures, and design experience reduce power consumption.
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ARM/StrongARM/XScale CPUs
Intel XScale
- 80321 600 MHz, 0.5 watts
PC CPUs
PowerPC
- Dual-core PowerPC MPC8641D 90nm, 2GHz, 1.2 V, 15-25 W
- PowerPC 750FX .13um, 900 MHz, 1.2 V, 3.6 W
- PowerPC 750CXe .18um, 600 MHz, 1.8 V, 6 W
- PowerPC MGT560 .20um, 56MHz 2.7 V, .5 W (Performance=56MIPS)
- PowerPC 440GX, 800 MHz, 4.5 W
- PowerPC 970, 1.8 GHz, 1.3 V, 42 W
- PowerPC 7400e, 1.0 GHz, 1.6 V, 30 W
AMD Athlon
- Thunderbird Athlon 750 MHz, 1.75 V, 43.8 W
- Thunderbird Athlon 800 MHz, 1.75 V, 45.5 W
- Thunderbird Athlon 850 MHz, 1.75 V, 47.92 W
- Thunderbird Athlon 900 MHz, 1.75 V, 50.7 W
- Thunderbird Athlon 950 MHz, 1.75 V, 52.5 W
- Thunderbird Athlon 1000 MHz, 1.75 V, 54.3 W
- Thunderbird Athlon 1400 MHz, 1.75 V, 73.5 W
AMD Athlon XP
- Palomino Athlon XP 1900+, 1.75 V, 68.1 W
- Palomino Athlon XP 2000+, 1.75 V, 70.5 W
- Palomino Athlon XP 2100+, 1.75 V, 72 W
- Thoroughbred A Athlon XP 2200+, 1.65 V, 67.9 W
- Thoroughbred B Athlon XP 2200+, 1.65 V, 62.8 W
- Barton Athlon XP 2600+, 1.65 V, 68.3 W
- Barton Athlon XP 3200+, 1.65 V, 76.8 W
AMD Athlon 64
- Newcastle Athlon 64 2800+ 512 KB, 1.50 V, 89 W
- Clawhammer Athlon 64 3400+ 1 MB, 1.50 V, 89 W
- Winchester Athlon 64 3500+ 512 KB, 1.40 V, 67 W
AMD Athlon 64 FX
- Athlon 64 FX-53 1 MB, 1.50 V, 89W
- Athlon 64 FX-55 1 MB, 1.50 V, 104W
AMD Sempron
- Sempron 3100+ (Socket 754) 256 KB, 1.40 V, 62 W
Intel Pentium 4
- Pentium 4 3.06 GHz, 81.8 W
VIA C3
pentium 4, 3.4GHz,512KB L2
VIA Eden-N
- Eden-N 533 MHz, 4 W
- Eden-N 800 MHz, 6 W
- Eden-N 1000 MHz, 7 W
Comparison of power consumption of some modern CPUs
Missing image
Power_consumption_graph.PNG
Power consumption graph
GPUs
ATI
- Radeon 9700 Pro, 45 W
NVIDIA
External links
- CPU power ratings (http://pub40.ezboard.com/f3dxtremeamdforum.showMessage?topicID=176.topic)
- Processor electrical specifications (http://users.erols.com/chare/elec.htm)
- Power ratings of AMD processors (http://www.amd-hardware.com/Watts.htm)
- Athlon XP 3200+ and Pentium 4 C power comparison (http://www.aceshardware.com/read.jsp?id=55000279)
- Component power consumption typical desktop computer (http://www6.tomshardware.com/howto/20021021/powersupplies-02.html)
- Minimum power supply for a Pentium 4 (http://www.experts-exchange.com/Hardware/Desktops/Q_20424890.html)