PC Peripherals pwm fans

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I've been hearing good things about PWM case fans. It seems they give the best of both worlds - high CFM when needed and low noise whenever possible.

The Arctic Cooling range seems interesting:

80 mm: Newegg.com - ARCTIC COOLING AF8025PWM 80mm Case Fan - Case Fans

120mm: Newegg.com - ARCTIC COOLING AF12025 PWM 120mm Case Fan - Case Fans

I think there's a 92 mm too.

The advantages I can see are:
1. The fan speed transitions smoothly as the cpu temperature varies (ie. doesn't just work at 3 speeds like a 5-7-12 mod)
2. Can be automatically controlled by bios or software (i suppose SpeedFan should work)
3. Uses all 4 pins on the motherboard fan header :hap2:
4. These particular Arctic Cooling fans can be daisy-chained so one header on the motherboard can control multiple fans

Does anyone have any experience / opinions on the Arctic Cooling or PWM fans in general coz I'm planning to pick up some for an HTPC (silent operation is critical)?
 
I don't understand your question. In motherboards that properly support speed control (my 5-year old K8NE Deluxe does this, for example) the fan speed ramps up with whatever temperature it's calibrated to (this is changeable in Speedfan) smoothly. No mods are required, and Speedfan properly controls them.

PWM fans (4-pin) need a properly supported 4-pin header on the motherboard. Most common mobos only have 3-pin headers for every position except the CPU fan, sometimes those 3-pin headers come without any speed control either. Most of the time Speedfan cannot work with 4-pin fans properly, requiring odd settings to get the speed to slow down correctly (and even then are non-proportional). The controls in BIOS work, if the BIOS has a setting for it (mine just says Enable/Disable, and pushes the fan to full speed once the temperature crosses 45 degrees). Once you hook a 4-pin fan to a 3-pin header, it runs full speed. To top it all, 4-pin fans cannot be run with a regular 5V or 7V mod, their controllers use duty cycling to set the fan speed.

The only use for 4-pin fans is as a substitute CPU fan, when you have a 4-pin header spare on the motherboard and need a fan quieter than the stock CPU fan. Some intel motherboards have two 4-pin headers, but almost every other mobo uses just the one.

I picked up a couple of PWM fans for my HTPC, to run off the CPU fan header and keep a little X2 4000+ cool. In the end Speedfan did not properly set the speed and the fan would run at full speed or not run at all. In the end I used two Silverstone case fans, and ran the cooler passive. Gets toasty but runs fine, I also use RMClock to keep the CPU volts under control so overall the system is safe.
 
Thanks for the feedback.

I'm actually doing something similar. My HTPC is a gigabyte 780g with an amd 7750 undervolted down to 0.85v which keeps it running pretty cool (practically at room temp even on full load) and more than enough clocks to run anything.

About having the pins or not, AFAIK quite a few new Gigabyte motherboards have 2 4-pin headers one for the CPU and 1 for the system fan (in any case I have them). Since I'm not sure whether the BIOS controls the Sytem fan header properly I wanted to daisy-chain a PWM case fan on the CPU fan header itself.

About your config a couple of questions:

1. Why would you rather have two case fans that presumably don't have a speed control than a cpu fan that has speed control? Are they quieter this way?

2. Why did you try to get speedfan to control the speed when the bios can do it?

Appreciate your feedback.
 
The case fans have thermal control, with a attached sensor. They are these ones: http://www.silverstonetek.com/products/p_contents.php?pno=suscool121&area=usa

One sensor is attached to the CPU heatsink, the other to the hard disks (this is the Antec NSK2480), when you see the layout you'll figure why I have them hooked up this way.

The fans run at ~500rpm all day, and only under stress do they hit their peak rpm, about 800. At max rpm I can hear them only if there is absolute silence (middle of the night), at regular running they are inaudible over the hard disk whine, which is louder.

To your specific questions:

1: I think I kind of answered that - yes, they just happen to run quieter on their own.

2: Because the BIOS is not tweakable (this is a Asus 690G board with some add-ins for HDMI and analog video). It just has a single Enable/Disable, whereas Speedfan gives me (mostly) a choice of the temperature I want it to ramp up at, and so on. This prevents it speeding up in normal operation, but brings in full speed for the times I really need it (for this rig, I try to get the full speed to kick in only after 55 degrees). My older K8NE-Deluxe has a much better control range, where the BIOS allows me to choose the start voltage, start temp and full speed temp. Obviously I let the BIOS handle it in that case. So I guess the answer is it depends.

If you have the headers then by all means give it a shot. I figure it's better to have a quiet fan in the first place and then work out how to connect it, rather than look at headers and see how to use them :)
 
cranky said:
I figure it's better to have a quiet fan in the first place and then work out how to connect it, rather than look at headers and see how to use them :)
Click to expand...

Touche. Thanks. I'll expand my search to fans with a temperature sensor.
 
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