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So, the OCZ cable can handle well the high-frequency noise that comes in with the electric current from the outside. But what if we launch a 3D game? There will appear low-frequency noise generated by the graphics card, rather than coming from the outside. The power consumption of the graphics card is irregular, with peaks following at the frame-rate frequency, i.e. a few dozen hertz.

The oscillogram below is taken in the +12v line in the Burn mode; it shows you the signal in the additional power connector of the graphics card (yellow) and in-between the OCZ cable and the PSU’s power cable (green). The X axis has a unit of 10 milliseconds; the Y axis – of 50mv:

The +12v power rail bottoms out under the graphics card with surges of 100-130mv that come at a period of 22 milliseconds, which corresponds to a frame rate of 45 fps. The cable from OCZ evidently cannot cope with the interference that comes to the power circuitry from the graphics card. The same goes for the +5v power rail. The oscillogram below shows you the signal on the additional power connector of the graphics card (yellow), i.e. between the graphics card and the OCZ cable. Green marks the signal between the OCZ cable and the power cable from the PSU. One unit of the X axis equals 10 milliseconds, and of the Y axis – 50 millivolts:

The filter influences the result here: the interference of the graphics card becomes smaller after it has passed through the OCZ cable. After the game scene changes, the power consumption of the graphics card changes slightly, too, and this can be seen in an oscillogram taken a few seconds after the previous one. The effect of the special cable from OCZ remains the same, though. The level of noise is lower on the output of the cable than on the input, i.e. on the graphics card’s additional power connector.

If we stretch the time scale in 10 thousand times, one unit of the X axis will correspond to 1 microsecond. The low-frequency constituents of the interference won’t be seen in the oscillogram then – the jaggies in the previous oscillograms will stretch out into almost horizontal lines. But high-frequency constituents will be perfectly visible:

The graphics card does not generate high-frequency noise working under a load. You can only see the same surges at a frequency of about 300kHz that come in from the outside and are more or less successfully suppressed by the cable’s filter: green denotes the signal in the place where the OCZ cable and the PSU cable connect, yellow denotes the signal between the OCZ cable and the additional power connector of the graphics card.

So, the filtering cable from OCZ Technology successfully eliminates the high-frequency constituents of the interference that comes to the graphics card along the power lines from the outside. If the graphics card were to produce such noise, the cable would handle it, too, not allowing it to pass from the graphics card to the PSU. As for the low-frequency constituents of the noise that appear when the graphics card is under a load, the OCZ cable cannot eliminate them.

 
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