Inadequate and Deceptive Product Labeling: Comparison of 21 Power Supplies

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

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PC Components	+3.3 Volt	+5.0 Volt	+12.0 Volt	Number	Perf.
IDE Hard Drive (RAID group)	Row 0 - Cell 1	0.80 A	2.00 A	4	112.00
Processor AMD Athlon XP 2100+, 1.75 V	Row 1 - Cell 1	Row 1 - Cell 2	7.49 A	1	89.88
RAM Module (128 MByte DDR-DIMM)	Row 2 - Cell 1	2.00 A	Row 2 - Cell 3	3	30.00
AGP Graphics Card (Nvidia GeForce 4 Ti 4600)	6.00 A	2.00 A	Row 3 - Cell 3	1	29.80
Motherboard with on-board devices	3.00 A	2.00 A	0.30 A	1	23.50
DVD-ROM	Row 5 - Cell 1	1.20 A	1.10 A	1	19.20
CD-RW	Row 6 - Cell 1	1.20 A	0.80 A	1	15.60
IEEE 1394	Row 7 - Cell 1	1.60 A	Row 7 - Cell 3	1	8.00
USB Devices	Row 8 - Cell 1	0.50 A	Row 8 - Cell 3	2	5.00
PCI Sound	0.50 A	0.50 A	Row 9 - Cell 3	1	4.15
Floppy	Row 10 - Cell 1	0.80 A	Row 10 - Cell 3	1	4.00
PCI-LAN	0.40 A	0.4 0A	Row 11 - Cell 3	1	3.32
System Fan	Row 12 - Cell 1	Row 12 - Cell 2	0.25 A	1	3.00
Processor Fan	Row 13 - Cell 1	Row 13 - Cell 2	0.25 A	1	3.00
PCI Modem	Row 14 - Cell 1	0.50 A	Row 14 - Cell 3	1	2.50
Keyboard	Row 15 - Cell 1	0.25 A	Row 15 - Cell 3	1	1.25
Mouse	Row 16 - Cell 1	0.25 A	Row 16 - Cell 3	1	1.25
Total Power Required	Row 17 - Cell 1	Row 17 - Cell 2	Row 17 - Cell 3	Row 17 - Cell 4	355.45 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.