X-bit labs

ATX Power Supply Units Roundup. Part VII (page 24)

Category: Other

by Oleg Artamonov

[ 09/04/2007 | 10:40 AM ]

The output voltages are stable, but not ideally so. The +5V voltage deflects most from the nominal value, but goes beyond the allowable range only at near-maximum loads. The +12V and +3.3V voltages do not leave the “yellow zone”.

The output voltage ripple is within the norm. I can only note the odd shape of the impulses on the +12V rail, perhaps due to the non-symmetrical dual-transformer design (it’s clear that the transformers are different – they have different markings and even different colors).

The first, external, fan is a Young Lin Tech DFS801512H (it is marked as “Ultra” but the original name and the UL certificate number help determine the actual manufacturer). It is an 80x80x15, 3200rpm fan.

The second, internal, fan is a Young Lin Tech DFC801012H (80x80x10mm, 3500rpm).

I should note that the use of “thin” fans involves one unobvious problem. The rotating speed being the same, a typical 80x80x25mm fan creates half as much static pressure as a typical 80x80x15mm fan. It is the static pressure that largely determines what volume of air the fan can pump through a dense arrangement with high aerodynamic resistance, so one 80x80x25mm fan can prove more efficient than a couple of “thin” fans.

Here, the fans start up at a speed of 1300-1400rpm and accelerate linearly to 2800-2900rpm after a load of 200W. As a result, the PSU is of average noisiness. It is not noisy, which is even a surprise considering its wattage and the cooling system consisting of two weak and thin fans.

The efficiency is 85% at the maximum and above 80% on average. The manufacturer’s website specifies a typical efficiency of 78%, but this must be just a reprint from the respective recommendations of the Power Supply Design Guide rather than a real number because the real efficiency of the PSU won’t drop so heavily even in an 110V power grid.

Thus, the Ultra X-Pro ULT-XF800S is a midrange high-wattage power supply. It doesn’t offer exceptional electric parameters and doesn’t work noiselessly, but it is capable of powering up an advanced PC configuration without problems. The aluminum case should be viewed as a design element because the material has no effect on the PSU, particularly on its cooling.