All types of computer equipment rely on DC cooling fans to prevent them from overheating. This includes everything from large servers to home PCs. The advantage of DC cooling fans is that they create less electromagnetic interference. This enables them to cool computer systems without disturbing processes with electromagnetic interference.
When choosing DC cooling fans for your computer, you might find that some of them are rated as 48VDC instead of 5V, 12V, or 24V. This is perfectly normal. VCD is simply another way of stating the amount of voltage that the fan uses. While the DC and VCD differentiation makes no difference, you should be certain to choose brushless models for your computer cooling needs.