OCZ StealthXStream 600 Watt PSU

Load Tests & Efficiency

Load Testing

Each power supply that passes through Overclock3D is put through its paces with a custom built load testing device. Using this device, the PSU is subjected to various loads and the performance measured. This gives a much better idea of performance levels than methods employed elsewhere.

Furthermore, during testing, the power supply's efficiency is tested by measuring the power being drawn from the mains supply.

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.

+3.3v Rail0w33w66w
+5.0v Rail0w50w100w
+12v Rail(s)0w240w420w

Load Test Results

In the graph above it is clear to see how well the StealthXStream handled increased loads with its Active Power Factor Control, doing a very good job of keeping the 12v and 3.3v rails up to ATX specification even at 100% load. The 5v however does appear to suffer at high load, however this is still well within the ±5% allowed on the +5v of the ATX form factor and so really is nothing to worry about.

Efficiency Test Results

On the specifications list for the StealthXStream, an efficiency of 83% @ 230v is claimed. As you can see above this has proved to be a pretty accurate claim, managing 82.77% efficiency at a load level most gaming setups could easily reach during stress. While 83% is nothing spectacular it is certainly up there with some of the best units we have seen at OC3D.

Temperature Testing

In our continuing efforts to make power supply reviews more thorough, rather than simply checking voltage stability, Overclock3D will now be recording the temperature of each PSU as it undergoes testing. Temperature recordings will be taken from the underside of the PSU's outer casing at 0%, 50% and 100% load levels using a laser infrared thermometer in an attempt to gauge how much heat is likely to radiate into the end-users case.

Temperature Test Results

The results obtained from this testing, which you can see above, came as quite a surprise to me. With a single 120mm fan, relatively small heatsinks and a medium to large power output, I would have put money on temperatures reaching the mid 40's or more. The unit manages a very comfortable 30 degrees celcius at 50% load and a slightly increased 34 degrees celcius at the full 100% load. This is undoubtedly down to the well laid out and spacious configuration of the internal components


A particularly hard part of reviewing a power supply is giving an accurate indication of the noise generated by the fan and electrical components. The normal procedure at Overclock3D has become to record the noise given off by the unit with a high quality microphone, to give a relatively fair representation of the pitch emitted. Unfortunately the usual equipment for this testing is not currently available so you will have to take my word for it when I say that this power supply is extremely quiet. I like my silence and I am certainly very easily irritated, but I can happily say that the pitch of the fan did not come close to annoying and the level of noise, even at high load was tolerable.

Let's head over to the conclusion page to see how the StealthXStream performed as a whole...
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Most Recent Comments

11-10-2007, 11:35:00

This is the PSU I use and its definatly the best one I have ever used.

Seriously, it is 99% silent.Quote

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