X-bit labs

ATX Power Supply Units Roundup: Part II (page 13)

Category: Other

by Oleg Artamonov

[ 04/25/2005 | 03:45 PM ]

Apart from cooling, the unit differs but slightly from the more traditional models. It has a Power-On switch (the switch is highlighted with red when turned on – should we considered it a “modding feature”?), doesn’t have any power-factor-correction circuits, and offers you a switch to choose the input voltage (110/220 volts). The PSU has two connectors for SATA drives (the cable is 50cm long to the first connector and 15cm more to the second one) and as many as nine connectors for PATA devices (three cables, 50+15+15cm each), plus an ATX12V and a 20-pin ATX connector (both on 50cm-long cables).

The load characteristics of this model are rather modest. Despite the total wattage of 300 watts it is closer to 250W units in the declared allowable currents.

The unit sustains the full load well, if not ideally. But this load isn’t very high in comparison with other units of the same wattage. Note also that the +5V voltage is rather high, being on the limit of the acceptable range.

There is no high-frequency pulsation of the output voltages under 300W load. You can only note minor spikes on the +12V rail with an amplitude of 20 millivolts at the moments when the inverter’s transistors are switched over. Low-frequency ripple can also be observed at 100Hz – its amplitude is 20mV for the +5V rail and 30mV for the +12V rail, and that is far below the acceptable limit.

The efficiency factor of this PSU is 85%. This is high, as is necessary for a fanless unit. The power factor is rather low, less than 0.7.

Thus, the Thermaltake PurePower W0029 may be an interesting option for people who are trying to build an absolutely noiseless, although not very powerful computer. The PSU’s load capacity is only comparable to 250W classic models as concerns the allowable currents (the PSU works fine, without overheating, at full load, but in order to create this full load in a real computer it is necessary that the load be evenly distributed among all of the PSU’s rails). Then, this power supply is rather expensive. It costs more than many higher-wattage units from Antec, OCZ, Enermax and others which are practically noiseless, too, at small loads thanks to their quiet fans and control over the fan speed. All in all, the Thermaltake W0029 is a very special product, and I’m inclined to regard it as a fashionable device rather than a necessity.