PSU Inside

This little sticker which sits on top of one of the screws makes sure you don't open your PSU, break it and then send it in to Zalman for RMA.


Zalman is using two heatsinks with heatpipes that transfer a lot of heat away from the center of the PSU to the rear. From there on the airflow that is created by the 140 mm fan exhausts the hot air. It seems this is a very viable concept because the PSU gets neither very hot nor is it loud.


The fan seems to be made by Zalman and has the model number ZF1425ATF. Since it is so big it can run slower to create the same amount of airflow as a smaller fan.

Test Equipment

• The PSU is connected to an APC SmartUPS which supplies clean 220V input.
• AC current is measured using a Peaktech 4010 desktop RS232 multimeter with 0.02A accuracy.
• To measure DC output voltages of the PSU we use a Keithley 2700 6.5 digit data acquisition system. All three input voltages are measured at the same time using a solid state switching system.
• Power Factor is measured using a generic Power Efficiency Meter.
• Measurements for Ripple Voltage were obtained using a 100 MHz Tektronix TDS224 Digital Storage Oscilloscope.

Fan noise measurements are performed with an IEC Type 2 Sound level meter and this setup.
It consists of three high-power resistors and a Socket A motherboard. The motherboard creates a small load which makes sure the PSU turns on (some PSUs require a minimum load). Since there is no hardware installed in the motherboard, its power draw is negligible. The three resistors create a static load of 320W (120W @ 12V + 50W @ 5V + 150W @ 12V) - a typical high-performance system. This setup is also used to determine the power conversion efficiency of the PSU.