OCZ ModStream 520W PSU Review


More info

Many people complain about their power supplies not giving enough voltage to the lines. Many use hardware monitors like the ones available in the BIOS, Motherboard Monitor, Winbond monitor, etc. These are all software based and can be inaccurate. They are approximate reading from the motherboards chips. So just because these software reading say lines are low does not mean it is the power supplies fault. There are many other factors included. Most of the main factors all occur within the motherboard and not the power supply. The voltages given from the power supply have to go through the motherboard before the software reading is taken. Therefore, there are different resistances on the motherboard that the power has to pass through. For instance, the power connectors on the motherboard could be damaged or not making good contact.

Other factors are resistances along the way to the motherboards voltage regulators. Also over time, especially when overclocking, the circuitry will degrade on the motherboard. All of these things can play a roll on how much voltage is lost on the way to the software reading. Therefore, the only true way to test if the power supply is doing its job is to take the voltage readings direct off the power supply and not the motherboard or the software readings. We find this way to be much more precise and accurate. The winbond chips on my motherboards have always been inacurate. For example, software such as Motherboard Monitor reports that my -12V line is running at 8 volts and the -5V line is running at 2.5 volts. A quick check with a multimeter revealed that these rails were perfectly fine.

The OCZ ModStream is ATX12 compliant. Not only does this specification require native SATA, PCIe and ATX12 motherboard connectors, but must also have a 70% efficiency rating, which should help reduce electricity costs. A power supply can never be 100% efficient due to the nature of electronics. A transformer has coil windings to generate an electromagnetic field and then must induce current in another set of windings. A certain amount of power is required to saturate the windings and generate the magnetic field, even though no work is being done.

A power transformer that is not connected to anything is a perfect example of a pure inductive load. An apparent power draw exists to generate the fields, but no working power exists because no actual work is being done. When the transformer is connected to a load, it uses both working power and reactive power. In other words, power is consumed to do work (for example, if the transformer is powering a light bulb), and apparent power is used to maintain the electromagnetic field in the transformer windings.