OCZ GameXStream more energy efficient than OCZ Powerstream

Shining Arcanine · Post by **Shining Arcanine** » Tue Nov 21, 2006 3:20 pm

http://techreport.com/onearticle.x/11302

The Tech Report has some numbers at the bottom of that page on the power consumption of a system with the OCZ Powerstream 520 Watt PSU and of the same system with an OCZ GameXStream 700 Watt PSU. Apparently, the GameXStream is more energy efficient at both load and idle and The Tech Report subjectively claims that it is quieter too.

Assuming that the OCZ Powerstream 520 Watt PSU has roughly identical efficient to the OCZ Powerstream 470 Watt PSU that SPCR reviewed, ignoring the possibility of same variance, and considering the 2 watt difference between the load AC power consumption in TR's numbers and SPCR's numbers, the DC power draw of the system TR used to test the two PSUs is 200 Watts DC, which means that the OCZ GameXStream 700 Watt PSU is approximately 88.9% efficient at a load of 200 DC Watts. Of course, this is plus or minus five percentage to account for the possibility of sample variance, the two watt discrepancy that I ignored and the possibility that the 470 watt version's efficiency is not identical to the 520 watt version's efficiency, but that is still pretty impressive.

Perhaps SPCR should ask OCZ for a review sample. The wattage rating might be overkill for typical computing, but if it is extremely efficient and the price is right, who cares?

jaganath · Post by **jaganath** » Tue Nov 21, 2006 3:59 pm

Perhaps SPCR should ask OCZ for a review sample. The wattage rating might be overkill for typical computing, but if it is extremely efficient and the price is right, who cares?

IIRC the OCZ GameXStream is based on the FSP Epsilon (FX700-GLN), which explains the high efficiency. Unfortunately it is also marred by a poor fan controller which ramps up fan speed far too much, far too fast; Oleg Artamonov (of Xbitlabs) has posted graphs on here comparing fan speeds w/ the S12-500, it's not pretty.

natethegreat · Post by **natethegreat** » Tue Nov 21, 2006 4:21 pm

JonnyGURU did a review of the GameXstream 700W Here is a quote from the review:

Next, we take a look at the oscilloscope readings.

While the power supply is subjected to the load tests, tiny fluctuations in voltage (called ripple) are output by the load tester. This output is then fed into an oscilloscope where they are converted into a legible waveform. Let's see how the OCZ GameXstream 700W did here...

Things were satisfactory until test 3. During test 3, I started to see ripple on 12V1 and 12V2 that was nearly 100mV. By test 5, the ripple was 100mV on 12V3 and 12V4 and had exceeded 100mV on 12V1 and 12V2. By test 6, the ripple on 12V1 and 12V2 had exceeded 150mV.

ATX specification has an "allowance" for 120mV. Mind you, test 6 was very stressful, pushing the power supply to it's limits, but it doesn't change the fact that the ripple exceeded spec and this is the first power supply to date I have had do this.

What's wrong with two much ripple? Well, if the voltage fluctuates too erratically, it can over work other regulators used to provide Vcore to the CPU, GPU, etc.

A representative of OCZ did find my findings concerning and asked that I return the unit for an exchange. I did so, and in the interim I obtained an FSP Epsilon 600W. The 600W version of the power supply the OCZ GameXstream is based on. In testing that unit, I found a good deal of ripple as well. When a brand new GameXstream was finally returned to me, I immediately plugged it in and found the same results as the first sample.

Fortunately, it is very unlikely any of us will have one of these power supplies at or above 400W, at least for any considerable period of time, but this high ripple measurement will be taken into consideration when calculating the performance score.

Based on the noise and the problems with ripple, I would stay away from this psu...

Oleg Artamonov · Post by **Oleg Artamonov** » Wed Nov 22, 2006 3:00 pm

natethegreat wrote:Based on the noise and the problems with ripple, I would stay away from this psu...

Hmmm... I've got only 81 mV ripple at full load (680W).
However, conclusion is the same: OCZ PSUs are far from the best.

Oklahoma Wolf · Post by **Oklahoma Wolf** » Wed Nov 22, 2006 3:33 pm

Oleg Artamonov wrote:Hmmm... I've got only 81 mV ripple at full load (680W).
However, conclusion is the same: OCZ PSUs are far from the best.

I'm finding that not all of these Epsilon based units are created equal... early revisions seem to have different filtering on the secondary side. The Epsilon I have sitting next to me uses two OST 2200uF capacitors in parallel on the 12v output, yet some of the innards shots of the Epsilon based Zalman and BeQuiet units I've seen seem to have one of those OST's replaced by four Teapo 470uF capacitors instead.

I know at least the Zalman unit tested here did a lot better for ripple than some of the reviews of the earlier revisions.