Introduction

OCZ's latest product is their EliteXStream power supply series, first introduced at CES this year. Shortly after the show, we had the chance to have a look at two production samples rated at 800W and 1000W. This new series is the first result of the OCZ and PC Power & Cooling merger following the acquisition last year. The EliteXStream series launches as the new top-end brand from OCZ, providing a high quality experience that we will see later. The target market is higher-end enthusiasts that have a need for greater connectivity and top quality. One look inside tells us what ODM is at the heart of the design, which dimmed our expectations a bit, but we ended up surprised by the performance these two power supplies delivered.

The two power supplies in this series come with similar specs, differing by just 200W of output. The difference lies in the important 12V rail which is slightly better equipped at the 1000W version. The smaller version provides 62A and the big brother ups the ante to 80A. If you have a need for the extra power, the 1000W should more than suffice; only extreme setups really require anywhere near that much power. Regardless, both power supplies come with the same number of connectors.

Appearance

Our early samples didn't have any printing on the box. The power supply itself is protected against damage while in transit by two foam pads. You get the standard accessories such as screws, a power cord, and a very informative manual in English, German, and French.

The power supply comes in black. There is a 120mm fan located on the bottom of the units, protected by a black fan grille. The grill is embedded in the housing so it doesn't stick out. This is important because some cases don't have any extra vertical space for a power supply; we have encountered this problem in the past, and it's good to see OCZ avoiding that pitfall.

An OCZ logo imprint adorns the side with EliteXStream 800W above. There is no real need for this feature, since the power supply will be hidden in a case and this side will face away from most windows. At least you can appreciate the logo prior to installation.

As with many PSUs, the back of the power supply has small hexagonal holes over the majority of the surface, providing good airflow and still obeying the EMI rules. Bigger holes can make the casing a bit delicate, plus there's greater risk of EMI. A small LED in the back shows the status of the power supply. It turns red if the temperature levels are too high, at which point the power supply will eventually turn off automatically.

Fan, Cables, and Connectors

A 120mm fan cools the power supply, made by Protechnic in China. It comes with the innovative name Magic; we hope it sticks to its name and provides good performance and low noise.

Sleeving covers all the cables harnesses, starting from the outlet of the power supply and going to the first connector. After the first connector, the cables hang free with nary a cable tie in sight. For the SATA and Molex harnesses, this isn't that important since they only have four cables. The length of the harnesses is very long, starting from 65cm/26". This is definitely good for larger cases and cases where the power supply is at the bottom. With these long cables, you can easily tuck the harnesses behind the motherboard tray for a nicer look - and more importantly, better airflow.

Each power supply has four PEG connectors, two 6-pin and two 6/8-pin. This will power any SLI/CrossFire setup, which should be satisfied with 744W on disposal even with the 800W model. (Tri-SLI configurations may require two additional PEG connectors, however.) There are eight SATA and eight Molex connectors available. Since the majority of users will have more SATA devices, we would prefer three SATA harnesses and only one Molex, but you can always use Molex-to-SATA converters if necessary while you can't go the other way. Surprisingly, we didn't find a 4-pin ATX12V connector for the CPU; you only get an 8-pin connector that cannot be split into two 4-pin connectors. This will be a problem for users with just a 4-pin jack on the motherboard, but OCZ told us they would ship an adapter for free for users that need it.

Internals

Opening this unit reveals a layout similar to what we've seen before. The power supply is actually made by Impervio, a fairly new company but one who has delivered good designs so far. Looking at the shot above shows one of the cleanest topologies we've seen, which makes it pretty easy for the novice to see the different parts of a power supply. The top area holds the input filtering stage; beside in the right third of the PCB we find the primary stage with main caps and IC. In the middle are the transformers and the left third houses the secondary stage. The coolers are a very light design, which allows air to come through and cool parts underneath them.

The printing on the PCB shows that it can work with 800W, 900W, or 1000W. It's good that OCZ didn't bother with a 900W version; that would have been pretty much useless since we already question the existence of the 1000W version.

The above mentioned filtering stage looks really impressive in this unit. The EMI filtering, X-caps, and coils line up nicely on the upper side of the PCB. On the right side below the heatsink, we find the rectifier bridge and Y-caps.

The primary stage houses three main capacitors made by Hitachi. They are each rated at 330µF and 420V, which is a good choice. We already saw this configuration in Silverstone power supplies, and the result was impressive.

Internals, Continued

Going over to the secondary side, we can see the large sister PCB with the security features and fan control. There are two temperature diodes attached to the control unit, which are both attached to the secondary heatsink. The PS232S from Silicon Touch Technologies is also no stranger to us, with many of the companies using this or similar chips in their power supplies.

On the left side of the sister PCB, we see three potentiometers that the manufacturer can use to adjust the voltage output after production. The problem with this is that it's possible for the potentiometers to come loose after a while, and the output voltage would change if that occurs. To prevent this there is a little drop of blue glue you can see on the picture below. It's still a slight risk, though probably 90% of all power supplies in the retail market use this approach. It's an easy way to lower production failure rates, since the manufacturer can easily adjust the output voltages, potentially saving a unit from the scrap heap.

The two temperature diodes attach to the secondary heatsink. The first one is on the left side and the other is on the right side.

The PCB shows several markings, including 12V rails numbered 1 to 5. Indeed this power supply was designed for several separated 12V rails, but many manufacturers are ignoring the specifications related to maximum amperage on a single 12V rail. Instead, they do whatever they think is best to provide a problem-free product.

All secondary capacitors come from Teapo, which we find in many power supplies. We have never had any problems with these caps so far.

Test Setup

As always, we tested with our Chroma ATE. The Chroma enables us to put a specific load on each of the rails. If you would like to know more about our testing methodology, equipment, and environment, please read our PSU testing overview.

We test an additional 10% above the highest load to see how the units perform with overload, both at room temperature and in a more stressful situation. To keep things somewhat reasonable we keep the ambient temperature at 50°C during the stress overload testing. Experience shows that many units can stand the overload at room temperature but will show problems with higher temperature and overload together. Only the best units will manage this without problems.

Loading Charts

We programmed the Chroma ATE with the following loads.

OCZ EliteXStream 800W Loads
PSU Load	3.3V	5V	12V1	Combined Output
10%	1.76A	1.89A	5.25A	86W
20%	3.52A	3.78A	10.51A	172W
50%	8.81A	9.44A	26.27A	430W
80%	14.10A	15.10A	42.03A	688W
100%	17.62A	18.88A	52.54A	860W
110%	19.38A	20.77A	57.80A	946W

OCZ EliteXStream 1000W Loads
PSU Load	3.3V	5V	12V1	Combined Output
10%	1.79A	1.92A	6.90A	100W
20%	3.58A	3.84A	13.79A	200W
50%	8.96A	9.60A	34.48A	500W
80%	14.34A	15.36A	55.17A	800W
100%	17.92A	19.20A	68.97A	1000W
110%	19.72A	21.12A	75.86A	1100W

DC Output Stability and Quality

As always, the stability of the rails is fine up to a certain load. At loads above 80%, the lines drop quite a bit, but they remain in spec. Heat does not seem to be a problem on this power supply, as the rails are similar even at higher temperatures. We have combined the DC output of both power supplies into each one graph to keep the overview. The distribution of both power supplies has been quite similar.

The different rails start above ideal and end below ideal, so the percentage of load regulation seems to be quite high. The 12V rail looks the best, showing a 3% drop. This is an average result among the PSUs we've tested, but we have predominantly looked at quality units so even "average" is good.

Current Limits

The current limiter on both power supplies is the same for the 5V and 3.3V rails. However, the 12V rails also show quite similar limits to our surprise. The 800W EliteXStream can pull a little more than 1000W from its 12V rail alone while the 1000W version can draw almost 1200W from this single rail. All rails combined is a different story however, since the maximum output is around 100W over each PSU's rated output.

Efficiency

We will be bringing two graphics of efficiency from now on. The first shows the efficiency at the load percentages and the second shows the efficiency at the different wattage outputs. The second one gives users a better comparison to other power supplies. If you know the amount of power your system requires, you can look up that load in the table below and see what efficiency the power supplies will provide.

To our surprise, the efficiency is higher than expected. We have seen similar layouts already and the efficiency never exceeded 83% with 230VAC. The 800W EliteXStream reaches its peak efficiency of 86% at a 350W load, and the 1000W version brings it up to 87% at a load of 350-400W. Both are excellent results. Another interesting aspect of performance is that both power supplies provide good efficiency over an amazing range of power loads. In both cases, the efficiency at almost any load a user would apply (at least on a system that would warrant the use of an 800W or 1000W PSU) is more than 80%. It is strange to see that the efficiency is so much higher with 230VAC than lower input voltages; normally the difference is only around 1%.

Acoustics

The EliteXStream runs very quiet at normal room temperatures. The 1000W version is around 5dB(A) louder at higher loads, but at equivalent loads the two units have similar acoustic readings. Only loads of 600W and more begin to cause noticeable noise; before that point, most users will not hear the power supply when it's in a case.

PFC

PFC readings are very good. With lower input voltages, loads from 20% up achieve more than .99 correction. 230VAC also shows good results, even though it's lower than the other two input voltages.

Conclusion

OCZ's new EliteXStream series brings very high quality to the market, and the choice of components was well done. The appearance is nothing special, since black PSUs are everywhere and 120mm fans are common. However, a PSU doesn't need to look special to be good. Both power supplies show they can perform well, and that's much more important than a fancy paint job that few will ever notice.

As we mentioned, the cable length and number of connectors is very good. With a minimum length of 65cm, the main cables will work with most large cases and still have sufficient length to be able to tuck them out of the way for better airflow. The number of connectors is good, though we're still torn about the need for eight Molex jacks; a third SATA harness might be preferable, with modern optical drives now switching to SATA. Still, there's no denying the greater versatility of Molex connectors - they can work with fans, lighting, some motherboards, and if necessary a converter is always an option for more SATA connectors.

A very important factor is the output voltage, where we need to look at the stability and also quality of the outgoing voltage. We test stability by putting loads on the rails that make the power supply sweat. The harder it works the more voltage drop we see on the rails. With only 3% of voltage regulation in the single 12V rail the EliteXStream can be proud, but the lower voltage rails fluctuate up to 6% - an average result. We measure output quality with an oscilloscope, looking at ripple and noise. Our results are acceptable, but still we measured up to 36mV on several rails.

On the efficiency side, we were surprised with the good performance. The 1000W EliteXStream reaches 86.84% efficiency and the 800W version 86.21%. Both results are excellent, and we measured more than 80% efficiency throughout the normal operating levels.

The noise levels are also good even at higher loads, generally staying below 30dB(A). It's only under harsher (i.e. warmer) conditions that the fan will start spinning faster, where noise then reaches more than 30dB(A). There was no other audible noise produced by the power supply except the already described fan. Even after a very long period of operation with loads of 500W (or lower), users should not notice any noise from this power supply.

The MSRP for the EliteXStream will be about $180 for the smaller and $230 for the larger version. Street prices may be lower or higher, but as these PSUs are not yet on the available we will have to wait and see. If OCZ can hit the MSRP, we expect many users will be very interested in purchasing EliteXStream PSUs. Looking at the 730W-1000W units we've reviewed lately, most prices are quite a bit higher than the price OCZ quoted to us. If this is what we have to look forward to from the OCZ/PCP&C merger, and if they can hit the price targets, OCZ will begin to exert an even greater influence on the market.