• 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
• CD-RW 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

For overall power supply wattage, add the requirement for each device in your system, then multiply by 1.8. (The multiplier takes into account that today's systems draw disproportionally on the +12V output. Furthermore, power supplies are more efficient and reliable when loaded to 30% - 70% of maximum capacity.)