Tom's Hardware > All Reviews > Components > Cooling > Stress Test: Power Supplies Under Full Load

Silverstone ST65ZF: Loud And Inefficient But Low-Cost

07:00 - Monday 11 July 2005 by Frank Völkel

The Silverstone ST65ZF showed poor efficiency and high operational noise under full load.

The graphic above shows the power supply connections and their length in centimeters: The Silverstone unit is one of the few test candidates with an EPS connector. All other connections are also featured.

Features

At the start of the week, the Silverstone takes its 650 watts into the next round of tests. Conspicuous about this power supply unit is that there is absolutely nothing much to write home about at first glance. Nonetheless, the manufacturer offers an EPS plug as well as an 8-pin P4 connector that enables the use of the power converter not only in the desktop but also in the workstation area.

The low-profile Silverstone for 650 watts maximum power.

Silverstone's connection leads - an EPS plug as well as two PCI-Express connectors are included

Type plate of the Silverstone - combined load at 650 watts

Test Results

The Silverstone ST65ZF with 650 watts has passed the test, even if a significant smell has developed around the platform. Sensitive users should keep some distance. However, the test data is convincing and remained within spec.

The Silverstone started with the slogan "Benchmark of stability and power" and made it through the 24-hour Live Stresstest. Details are shown in the table below. All test data ware within spec and not give reason for critizism. However, the extremely loud operating noise under full load could be improved. 68 dB(A) are comparable to the PC Power & Cooling.

Silverstone ST65ZF (650 watts)
Test Phase 1
Test Description	Lower Limit	Upper Limit	Result
Increase load from 20% to 100% of nominal load limit	130 watts	650 watts	Passed
Test Phase 2
Test Description		Load	Result
Steady load at 100% nominal load		650 watts	Passed
Test Phase 3
Voltage Stability
Power Rail	Measurement	Min/Max according to ATX Spec.	Result
+ 3.3 V	+ 3.24 V	+/- 5% (+3.14 to +3.46 V)	Passed
+ 5 V	+ 4.89 V	+/- 5% (+4.76 to +5.25 V)	Passed
+ 12 V	+ 12.00 V	+/- 5% (+11.4 to +12.6 V)	Passed
+ 12 V CPU	+ 11.89 V	+/- 5% (+11.4 to +12.6 V)	Passed
+ 5 V Standby	+ 5.03 V	+/- 5% (+4.76 to +5.25 V)	Passed
- 12 V	- 12.65 V	+/- 10% (-10.8 to -13.2 V)	Passed
Ripple
Power Rail	Measurement	Min/Max according to ATX Spec.	Result
+3.3 V	41 mV	50 mV (Peak-Peak)	Passed
+12 V CPU	38 mV	120 mV (Peak-Peak)	Passed
Further Data
Value	Measurement
Noise Level (max.)	68 dB(A)
Voltage	212 V
Current	4.09 A
Cos Phi (Phasenverschiebung)	0.99
Efficiency	75.4%