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Inadequate and Deceptive Product Labeling: Comparison of 21 Power Supplies

Test Profile For Power Supplies - Power Consumption Of A High-Power PC

PC Components+3.3 Volt+5.0 Volt+12.0 VoltNumberPerf.
IDE Hard Drive (RAID group)0.80 A2.00 A4112.00
Processor AMD Athlon XP 2100+, 1.75 V7.49 A189.88
RAM Module (128 MByte DDR-DIMM)2.00 A330.00
AGP Graphics Card (Nvidia GeForce 4 Ti 4600)6.00 A2.00 A129.80
Motherboard with on-board devices3.00 A2.00 A0.30 A123.50
DVD-ROM1.20 A1.10 A119.20
CD-RW1.20 A0.80 A115.60
IEEE 13941.60 A18.00
USB Devices0.50 A25.00
PCI Sound0.50 A0.50 A14.15
Floppy0.80 A14.00
PCI-LAN0.40 A0.4 0A13.32
System Fan0.25 A13.00
Processor Fan0.25 A13.00
PCI Modem0.50 A12.50
Keyboard0.25 A11.25
Mouse0.25 A11.25
Total Power Required355.45 W

On the basis of the recommendations from AMD and Intel, THG drafted a load profile that corresponds to the power of a typical high-end computer. We tested the performance of the various power supplies on the basis of defined resistive loads. A special test rig simulated the current consumption of typical components within a PC system. On this rig, the current strength is simulated for each voltage range (3.3, 5 and 12-Volt) by means of plug-in jumpers and controllers. The power consumption of a high-end computer constitutes the basis for defining the relationship in the percentage of load distributed between the individual voltage ranges. The power demand on the individual channels is evaluated on the basis of this loading. The testers measure whether the individual operating voltages remain stable at the set loads. At the same time, the lab technicians calculate (regardless of the manufacturers' specifications) the power that each power supply generates with a stable output voltage. The test result also includes whether or not the power supply actually keeps to the manufacturer's specifications. The power coefficient indicates, as a percentage, the ratio between the nominal power and the manufacturer's specifications.