Stephen's Blog

To anyone who hasn’t considered it, it may seem counter-intuitive that smaller fans are noisier than larger fans (at least when producing the same airflow). This is simply because a larger fan can run much slower than a smaller fan and produce the same airflow. When designing computer cases, it is better to opt for larger (120 mm) fans than smaller (80 mm) fans.

One of my machines is stacked with 5 PCI devices (3 TV tuners for MythTV, a raid card, and a video card.) The battery backup unit on the 3Ware 9650SE raid card had begun complaining about overheating, and I wanted to see if I could run the video card without the fan (this tiny little fan was generating more noise than the rest of the fans combined!) So I basically needed to introduce some extra airflow to the expansion slot area of my machine.

The Antec P180 has an exhaust duct with an area for an 80 mm fan designed to cool the video card.  Unfortunately, it is a small, noisy fan and did not provide increased airflow to the entire array of my PCI devices. Furthermore, the very top interfered with my large CPU fan, so I decided to give my new Dremel a run and modify the duct to accept a 120 mm fan.

The operation was pretty simple. I just needed to cut out a larger hole and make sure there was still a good air tight seal, and that the duct remained structurally sound. I wasn’t sure whether to “push” or “pull” the air, so I wanted to make sure the fan could be easily removed and turned around.

Super glue was used to reattach the missing top piece. I used some black electrical tape to seal the holes. I wanted to use super glue, but didn’t have any available. The electrical tape has been adequate though.

So far, the battery’s temperature has been significantly reduced, and the video card has been able to run without a fan. In order to achieve this last trick, I had to take the heatsink off the card and turn it 90 degrees such that the fins ran parallell with the airflow.

Between this mod, and replacing the stock CPU cooler with a ZeroTHERM FZ120 (which I’m very pleased with), my machine is virtually silent.