Introduction:

It wasn't too long ago that computer power supply units (PSUs) did not receive any attention whatsoever. You bought a computer (or if you were adventurous, just a case) and it came with a PSU - that was the end of it. You didn't care what the PSU was rated for, or who it was made by, or whether it had any additional "features" - and who would, if it were not necessary. Things have changed in recent years with computers requiring more power to drive faster CPUs, (CPUs with perhaps more than one core), spin more HDDs, and keep mega-videocards going. No longer can a system builder not care what PSU is being used in his/her system: It can be as important a decision as deciding what other components go into a system, since a good PSU effectively safeguards one's investment in a potentially pricey system.

The rise of the aftermarket PSU market can be closely linked with the emergence of the case modding scene and general proliferation of computer parts. Case modders, being the inventive and ingenious people that they are, were always looking for ways to make their PSU work and look better in their system, whether it was changing out one PSU fan for another, braiding the cables to improve airflow, or adding lighting to the interior. Manufacturers were not about to let this market go untapped, and so they began producing PSUs that came with many of these features - as they have done with so many other things started by case modders.

Thus, the market began to fill with not only higher-quality PSUs, but also PSUs that came with coloured and lit fans, sleeved cables, quieter fans, and a whole assortment of additional features. Indeed, there are so many PSUs available today that it can be confusing to distinguish between them all. I'll try to alleviate some of that confusion by looking at the latest offering from OCZ, the 520W ModStream PSU, which offers many features that make it ideal for enthusiasts. But, most importantly, can it deliver a clean "stream" of power?

Specifications:

With our positive review of the OCZ PowerStream, I had high expectations for the ModStream, the next generation of PSUs from OCZ. If you had read the aforementioned review, you would have noticed that the main complaints about that PSU were the lack of a modular cabling setup, and absence of sleeving on most of the power connectors. The ModStream solves both of these problems, showing that OCZ is improving their products with each release, rather than just repackaging a similar unit for resale. The ModStream PSU also supports new standards such as BTX, PCI Express, and EPS12V (for a 24-pin mobo power connector) as well as current standards like SATA. Thus, you can be sure this PSU will work with most any setup; the 520W rating also helps in this respect, but a 450W version is also available.

• More specifications available here.

A PowerWhisper 120mm fan provides cooling for the unit, which seems to be a popular size for PSUs nowadays. It has a clear fan/frame and also is also lit by blue LEDs when operating - a nice touch that compliments the chrome/metallic black finish exterior of the PSU, making it a highly attractive unit. The back has both a hard on/off switch and a voltage selector, which can be set depending on what voltage level your continent's power grid uses.

When first opening the package of the ModStream, one can easily tell that this PSU was designed with enthusiasts, gamers or anyone with a powerful system in mind. Besides being a heavy and high-quality looking unit, the package was well designed with the modular cables in a separate box with clearly labeled contents. The PSU was also well-packaged to ensure that it wasn't damaged during shipping. There is also a certain awe factor in looking at something with a mirror-like finish to it, complete with fully-braided cables that are also UV-reactive.

The bright package.	What's included.
Dark chrome finish.	Adaptable mobo power connector.

Besides the PSU and the modular cables you also get an AC power cord (also braided and colour coordinated with the rest of the PSU), mounting screws, coloured velcro straps and plastic tie-wraps for cable management - this is certainly a complete setup that left nothing for you to be searching for once getting everything setup. There are only two connectors whose cables are hard-wired to the PSU, those being the motherboard connectors, the ATX and ATX12V plugs. As virtually all motherboards will need both of these connecters plugged in, this is not a problem.

Newer motherboards are using the EPS or ATX 24-pin connector; while this is needed for the latest generation of technology it has created a problem since there are still many motherboards out there that still use the older 20-pin connector. The ModStream PSU solves this problem nicely by having separate connectors for the 20 and 4-pin parts; the 20-pin connector has a groove that the 4-pin connector can easily slide into thus allowing easy conversion between the 20 and 24-pin standards. The 4-pin connector slides on to the 20-pin connector in such a way that it cannot come loose from it when they're connected to the motherboard, a nice attention to detail. They are braided separately and come tie-wrapped together. This adaptable connector is a better solution to the problem than using a separate adapter cable that only takes up more room and adds another place for cables to come loose.

Modular system for power connectors.

120mm blue LED fan.

Specifications.

Perhaps the most vaunted feature of this PSU is the modular cables it provides. None of the peripheral power connectors are directly hardwired to the PSU; rather cables are provided that plug into connectors right at the PSU itself. The advantages are obvious: Firstly, one need only use the cables that are needed for one's system, and the correct type of cable with the right connectors can be used. This allows for less clutter in a system and hence better airflow, and less trouble for you as well, as you'll no longer need to bundle and tie up unused cabling and try to stuff it into a crevice in your case only to find that you need one cable from that huge bundle.

Additionally, the cables themselves are quality-made, being wrapped like rounded IDE cables in both an EMI-reducing material and a clear plastic sheath. These cables glow nicely under UV light, so if you already have such a setup in your rig, this PSU will add another nice effect. Furthermore, the ends of the cables near the connectors are covered in heatshrink, adding more professionalism to the unit. As for the assortment of cables, here's what you get.

• 2 cables each with two 4-pin connectors

• 1 cable with a 4-pin connector and a 4-pin FDD connector

• 1 cable with one 4-pin connector

• 1 cable with a 6-pin PCI Express connector

• 1 cable with two SATA power connectors

Since the PCI Express and SATA cables appear to use the same style of plug to connect to the PSU, each of them is colour-coded so that you will know where to plug each one into. As for cable length, all of the cables except for the cable with the sole 4-pin connector are 49cm or 19" on their longest length of cable. The shorter "stub" is 24cm or about 9" long. (It's worth it to note that for the cables that have two available connectors, you can use any 4-pin connector to hook into the PSU, so you could have the cable plugged into the PSU at either of the end connectors or the middle one depending on which better suited your setup.) The sole 4-pin connector cable is about 59cm/23" in length. These lengths ought to be able to reach most devices in most cases.

Rear has hard on/off switch.

Modular cables.

Other accessories.

The 520W version of the ModStream PSU is rated for 28A on the +3.3V line and 52A on the +5V, but these combined cannot exceed 260W of power. The +12V line is also rated for 28A, yielding its max wattage to be 336W. The -12V, -5V and +5VSB ratings are the same for both the 520W and 450W versions of this PSU, but the 450W version has slightly lower ratings for the +5V and +12V lines.