OCZ ModStream 520W PSU Review


What's in the box

The power supply itself is wrapped in a custom-made bubble-wrap “box”. Inside the main box is a separate cardboard container with all the cables, a well-written manual, zip ties, bonus Velcro wraps and an unusually beautiful power cord. The power cord features copper mesh around the cables, a circular ferrite bead near the connector, and a translucent blue plastic, which matches perfectly with the look of the power supply. The included power cord is more flexible than a standard black or grey power cable. The included EZmod power cables consist of:

  • 1x single 4-pin cable
  • 2x dual 4-pin cables
  • 1x dual 4-pin cables with floppy connector
  • 1x PCI Express 6-pin connector (17”)
  • 1x dual SATA connector (25”)

All of the EZmod cables are EMI shielded (with copper braiding to reduce electromagnetic interference) and react to UV lighting. The copper braiding, which is actually silver in color, covers the actual wires, and clear plastic tubing encases the copper braiding. The ends of the tubing are zip-tied and then encased in blue heatshrink is to keep the stuffed cables tidy. All cables are molex based, except for the PCIe and SATA cables which plug into a 6-pin connector. Because the SATA cables are native, they have 5 lines (an extra +3.3V line) instead of the 4 used in SATA power adapters. Although current SATA drives do not use the +3.3V line, SATA2 might. The PCIe cable has a ferrite core encased in the heatshrink to prevent radio interference. The cables are a little stiff, but not unflexible, and the plastic tubing likes to cling when it contacts other tubes. These properties pretty much keep the cables in the position you put them in, and works best when the cables are clustered together, branching off as needed.

A closer look inside
We decided to take a look at the inner workings of the power supply. The cover is fastened to the power supply chasis with four screws (one of which is covered by a voided warranty warning). Once removed we could see the quality and craftsmanship that went into this power supply.

The 120mm fan’s cabling is carefully tucked behind the transformer’s large black-anodized aluminum heatsinks.

There is a small amount of space between the circuit board and case, probably to fit an 80mm fan using another design. The included 120mm fan is crystal clear and has 4x 5mm blue LEDs at each fan corner. There also appears to be extra circuitry modules for line protection. Each molex connector is individually wired (unlike the X-connect which power all ports from one line) which should help stabilize the unit’s rails.

What are “Rails?”:
PC enthusiasts sometimes talk that their “rails” are low and that they need a new power supply. First off, the “rails” that they are referring to are the 3.3V, 5V, and 12V lines that come off the power supply. The 3.3V and 5V generally power the digital devices like the motherboard, PCI slots, AGP slot, etc. The 12V is usually for motorized devices like the hard drives, CD-ROM, fans, etc.

These lines are rated to run at a certain specification, usually somewhere around plus or minus 5%. Technically, if these lines stay within this margin, the system should run fine with no instabilities but if they do run out of specification a number of problems can arise. Usually power supplies go under the minimum voltage when used over a long period of time.

When the rails are low this usually leads to blue screens and various other instabilities like random reboots. When these lines are overvolted problems arise again like drive failure, blue screens, damaged drives and damaged motherboards. Therefore, it is easy to see why it is important to have “clean” power – power that is stable, does not fluctuate, and within a tight tolerance.

High-quality power supplies also help protect your systems. A good power supply will not be damaged during a power outage, brownout, or spike (like 2,500V from a lightning strike). Decent power supplies have an extremely low current leakage to ground of less than 500 microamps. This safety feature is important if your outlet has a missing or an improperly wired ground line. I experienced the ModStream’s power protection first hand when I accidentally arced the wrong wire during testing and shut down the entire system. I thought my entire system was toast, but everything was fine after resetting the power supply. You never realize how important this protection is until you need it.