Running Cool and Quite

[svasutin]

So lately I've been trying to get my home theater PC's quieter and cooler. BTW, all my systems are AMD based, so Intel systems are different. The video cards are always ATI All In Wonders (agp or pci-e). Artic Silver 3 was used as the thermal grease (trying to use this stuff up before I go with 5).

I purchased a mid tower case with thermisters to monitor the CPU, VGA, and HDD temps. This is in addition to the Asus Probe utility. I also have a cheap Radio Shack audio meter (which only goes down to 50dBA). Connected to the nexus front panel fan controls are the top, side, front, rear, CPU, and VGA fans. All fans were tested at the barely on to full on settings. Except for the CPU and VGA, full off was also tested.

First, I found the front case fan to be near useless. If the front fan is mounted below your hard drives, then it only serves to raise your system and CPU temp. I find placing the front fan so it blows on top and bottom of your video card to help with the video card cooling, but doesn't affect the overall internal system or CPU temperature. There is a +3 C difference if your front fan is below your hard drive(s); there is a -1 to -2 C for the video card if the fan blows around the video card. If you can't mount your fan above your hard drives, then turn it off.

The side and top fans helps with overall system temperature 2 C each. Ultimately, the rear exhaust fan is the most important. The side and top, at full speed, only provide 4 C of cooling, where as the rear fan at full speed provides 6-8+ C of cooling for your system, VGA, and CPU.

I think what I found was, one wants the side fan to blow closer to the CPU, but also around the top of the VGA. The rear fan serves to suck the heat from the video card and CPU. The front fan blowing over the top helps the heat from the VGA and CPU to go out the rear, rather than back up towards the CPU.

The CPU I used was a Sempron 2400+ (socket A); Sempron's just seem to always run hot (48-55 C). I tried all aluminum, all copper, and al+cu heat sinks. By far, all copper seemed to be the best, followed by cu+al, and the all aluminum was 8 C higher than the all cu heat sink. Since the al+cu fan and heat sink I purchased was quieter, I went with it instead of the all cu.

Unfortunately I couldn't find a VGA cooler that fit the ati aiw 9600xt agp 8x card, so, as stated above, I just connected the fan to one of the front panel fan controls.

To heat things up, I tested with Furturemark PC Mark 05. Overall testing was done over a week, and took more than 12 hours. PC Mark was run 3 times to ensure the temperature stabilized.

I found the test-time took over 16 minutes when the CPU temp was at or above 50 C, and saved about 1 minute when the temp was below 50 C. The difference between having the top, side, and front fans set to off, the CPU, VGA, and rear fan to barely-on was 9 C. My CPU ran at 53 C; having the CPU fan set to full, allowed the CPU to run at 44 C. Generally, the VGA ran between 39 - 55 C, and is almost always hotter than the CPU. Turning every thing on, allowed my CPU to get down to 41 C, but man was it noisy.

Noise

The loudest fans were the VGA fan followed by the Side window fan. The front fan makes no noise as far as I can tell. The CPU and rear fans make a hum sound, and the top and side fans have the familiar sound of air rushing. I found Aero Cool 2-ball 80mm aluminum case fans to be the quietest fans I tested; regardless of which 80mm fan was used, the side fan always made the most noise between the top, rear, front, and CPU.

Generally, I am keeping the side and top off, the front, VGA, and CPU fans to barely, with the rear fan half way between barely and full.

At idle, CPU=44, system=28, and VGA=40.

At full, CPU=49, system=32, and VGA=50

I am wondering, what are your average system temperatures?

What is your average CPU temperature?

And what temperature does your video card run at?

Finally, does anyone know where I can get an audio meter that can measure between 17 dBA to 60 dBA?

[LLXX]

55°C is perfectly fine for full-load CPU temp, so if you can slow down the CPU fan some more it'll be a bit quieter without risking overheating. Anything over 70° is not recommended, but mid 60s are alright. Remember, the CPU won't normally be running at full load for extensive periods of time in normal use.

It's normally a tradeoff between cooling and sound; the better cooling you want, the louder it's going to be. Of course, water cooling is an exception to this - it's very quiet but cools very well too.

My temperatures (in a nominal 16°C (60°F) room):

Idle: System:20, CPU:27, Vid:don't know exactly, heatsink feels slightly warm (fanless GeForce FX5200)

Full: System:25, CPU:52, Vid:probably ~50° - heatsink feels very warm

But I have a total of 12 fans, so it's not exactly quiet...

Edited February 14, 2006 by LLXX