The computer is housed in a Lian Li 6070 case. If you are not familiar with this case, it looks like this. Lian Li There are only 3 ways for air to get in or out of the case. The primary intake is this small filtered opening on the bottom of the case, in the front. The primary exhaust is through the power supply. The other potential source of airflow is this 80mm fan opening on the back with a grill that is too restrictive.
During my efforts to quiet the case, I stumbled onto the discovery that the case doesn't have enough airflow. I noticed that when I took the side panel off of the case, that in about 90 seconds the CPU temperature dropped 6 degrees celcius. Experimenting with different CPU coolers lead to similar results - Taking the side panel off, with no other changes, dropped CPU temperatures between 6 - 9 degrees celcius for each cooler.
Also, I have noticed that after running the computer for an hour or two, the fan in the Nexus PSU ramps up enough to be annoying. I attribute this noise to the gradual build up of heat after the computer has been running for a while with insufficient air flow.
Here are the components that I am working with:
- Motherboard - Gigabyte GA-7N400 Pro 2
CPU - AMD Athlon XP 2400+
CPU cooler - Thermalright SI97A
CPU Fan - Yate Loon 92 mm "Silencio special edition", running at 5 volts
Video card - ATI Radeon 7000 64 meg
What I've tried so far with the results for each
- Adding an exhaust fan on the rear of the case - I added a Yate Loon D80SL-12 fan blowing out of the case. At 12 volts the CPU temperature dropped about 2 degrees, but the noise was much louder. I don't know if this would slow the fan in the power supply, as the exhaust fan is louder than the power supply. This is not an acceptable solution as it adds noise, but less cooling, than just removing the case side panel. At 5 volts, there is no definite change in CPU temperature. By itself, I consider this experiment a failure.
Increasing voltage on CPU fan - I tried running the fan at the regular 12 volt level. The temperature didn't change. From outside the case, the noise is about the same, or maybe a little louder. I think this is a testament to the small amount of airflow that the Thermalright cooler needs to be effective. Also, I think it reinforces the idea that this case needs more outside air. Moving more of the same warm air inside the case doesn't help cooling. For now, I plan on leaving this fan at 5 volts.
Using dual fans on the front intake. There is a mounting point for two 80 mm fans on the inside of the front of the case. I have mounted 2 YL D80SL-12 fans, running at 5 volts. They draw air from the filtered intake at the front of the case on the bottom. Adding these fans has had no effect on the CPU temperature. However, they are quieter than the fan on the power supply. I can't hear them from outside the case. I plan on leaving them in place, as they direct airflow over the hard drive that is located in the lower drive cage.
- I have removed the filter and bracket for better airflow. I also cut out some of the inner supports. What used to look like this
- Now looks like this.
However, this change has not affected the CPU temperatures.
- Cutting a 120mm hole in the bottom of the case. There is room on the floor to cut a hole and cover it with one of those 120 metal mesh filters. I think this should help the airflow. I think this holds the most promise.
- Adding another 80 mm hole to the back of the case, below the existing hole. My thought is to use one for intake, and one for exhaust. I'd be especially interested in thoughts about this idea. Would some of Bluefront's ducting help? Should the exhaust fan be the upper one to keep the intake from recirculating the heated air?
- Getting a windowed side panel and adding a blowhole either with or without a fan. There are prefabricated panels for Lian Li 6xxx series cases. They have a window already in place. This is kind of low on my list of ideas. But if it will help the cooling, I'm willing to give it a try.
