Desktop Computer Power Consumption

computer power supply

Your desktop computer power consumption may be causing stability problems with your computer. Troubleshooting a PC Power Supply isn’t that difficult. Various PC parts will use either 3.3 volt, 5 volt, or 12 volt. The 3.3 and 5 volt leads usually power digital circuits, while the 12 volt leads provide power to fans and drives. The common form factor used in computers today is the ATX. This power supply has a single, twenty-pin connector. Some typical symptoms of a bad power supply include: Dead system, partially dead system, and random rebooting. If the PSU’s fan quits working, replace it immediately.

Desktop Computer Power Consumption

Desktop Computer Power Consumption Table

The diagram below indicates the approximate desktop computer power consumption per device. Use this chart to determine what size power supply you should purchase. Keep in mind it’s always best to buy a quality name brand power supply that exceeds the wattage you’ll need to power your computer. A budget computer supply will only cause you problems.


Component Requirement Line(s) Used
AGP Video Card 30 – 50W +3.3V
Average PCI Card 5 – 10W +5V
10/100 NIC 4W +3.3V
SCSI Controller PCI Card 20W +3.3V and +5V
Floppy Drive 5W +5V
CD-ROM 10 – 25W +5V and +12V
DVD-ROM 10 – 25W +5V and +12V
10 – 25W
+5V and +12V
7200rpm IDE Hard Drive 5 – 20W +5V and +12V
10,000rpm SCSI Drive 10 – 40W +5V and +12V
Case/CPU Fans 3W (ea.) +12V
Motherboard (w/o CPU or RAM) 25 – 40W +3.3V and +5V
RAM 8W per 128MB +3.3V
Pentium III Processor 38W +5V
Pentium 4 Processor 70W +12V
AMD Athlon Processor 70W +12V

Desktop Computer Power Consumption Conclusion

A gamer or high performance will have greater demands and are more sensitive to desktop computer consumption than a budget PC. A good rule of thumb is to buy a better power supply, such as a Corsair PSU.

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