X-bit labs

Roundup: 14 Power Supply Units from Thermaltake (page 24)

Category: Other

by Oleg Artamonov

[ 07/28/2006 | 08:34 AM ]

The cross-load characteristic of this PSU is very good expect for the +3.3V line whose voltage changed rather too much depending on the load, although it always remained within acceptable limits. The +5V and +12V voltages are very stable. Moreover, none of the voltages deflected by more than 5% in the whole range of loads allowable for this PSU. As a result, the cross-load diagram is shaped like a regular rectangular which is usually observed with power supplies that have independent voltage regulation.

Alas, the PSU couldn’t yield its promised 500W of output power – its protection was triggered at a load of about 475W. However, it escaped the ill fate of the XP480 and the XP550 models and worked normally under any loads below 475W. I guess the number 450 in the name of the original CWT model is indeed true and Thermaltake shows some cunning here, declaring a pretty-looking but wrong number in the specs.

At a load of 475W (the highest load the PSU was stable at), the voltage ripple was 45 millivolts on the +5V rail, 73 millivolts on the +12V rail, and 26 millivolts on the +3.3V rail. So, the ripple was close to the allowable maximum of 50 millivolts in the first case; in the other two cases there is a solid reserve yet. Only high-frequency pulsation was observed on the +3.3V rail; both low- and high-frequency pulsations were on the remaining two rails, the low-frequency constituent prevailing.

The PSU has a TT-1225A fan manufactured by Adda (the AD1212US-A71GL model). A transparent piece of plastic covers one half of the fan. One of its ends isn’t fastened and contributes to the PSU’s noise. As a result, the PSU produces a quiet but distinct humming at any load.

The fan speed is controlled in Thermaltake’s traditional way. It’s even funny that the fan speed management doesn’t vary much between the different actual manufacturers of Thermaltake’s PSUs. The fan rotates at about 1150rpm under loads below 200W, but then its speed begins to grow up linearly to 2500rpm. So, its noise parameters are average. It is not exactly quiet, but will satisfy a majority of users nonetheless, especially if you take care to secure the mentioned piece of plastic well…

The efficiency of this power supply is unexpectedly low at 68% under maximum load and 76% at best. The power factor is never below 0.7 thanks to passive power factor correction, but a high efficiency would be of much more use for home users than a high power factor.

Summing it up, I’d say the W0093 is a well-made midrange product, but its real wattage is 450W rather than 500W. It delivers stable voltages, works quietly and offers all the necessary connectors. On the downside are its low efficiency and rather strong low-frequency pulsation on the output, but this will hardly be a problem for ordinary users. Thermaltake has also greatly improved since the XP480 and the XP550, overstating the wattage of this PSU by only 50W rather than by 50%! :)