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New HTPC Excessive Fan Speed/Mobo Temp

Last response: in Systems
May 26, 2010 7:03:37 AM

Hey guys, finally got my HTPC up and running. I ordered an OEM Athlon IIx3 425 2.7GHz as I believe this would be PLENTY for an HTPC. I used my 955 BEs stock cooler to cool it, since its OEM and didn't come with a HSF.

But for whatever reason, the fan increases in RPM steadily after start up until it's just screaming. I at first assumed it was running at a reasonable speed and the bearing had unseated, so I opened it up and pressed on the center of the fan and got a re-assuring click as it dropped down lower.

I restarted and once again, lots of noise that increases with time. I opened speedfan to check temps and noticed the fan's RPM was over 7000. Yes, 7000.

Here are my temps:

Temp1: 45-50
Temp2: 40-50
Core: 37-40

Now, Im pretty happy with the core temp, but the Temp1 and 2 concern me, that seems pretty warm to me. I will admit that the HTPC is in an entertainment center, and doesnt have alot of room on each side. I have considered cutting holes in the walls of the entertainment center where the vents and fans are located in an effort to increase airflow, or possibly moving the HTPC entirely. I would like to avoid moving the HTPC because it's in an optimum location for function.

The case is: Antec HTPC case

As you can see its compartmentalized and has dual 120mm fans right by the motherboard/CPU to exhaust hot air out the right side. In my situation, I only have about .5-1" clearance on the right side of my entertainment center.

So here's my question: Is the motherboard increasing the CPU fan speed because of Temp1 and 2? There is only 1 fan header on my ASUS 785G motherboard, so I dont have anywhere else to plug the fan in. Being that it's an HTPC case, my aftermarket HSF sizes are limited.

Also, I can manually set the fan speed to 15-20% (2000-2500 RPM) in Speedfan, without any change in my temps and the noise is gone. The wife flipped out today at the noise and shut it down in anger. Since every restart it sounds like a jet engine getting closer and closer(I work on F-16s, so I know that it does in fact sound like a turbofan engine) and until I get into windows, I cant manually set it lower.

Also on a sidenote, I am using a wireless keyboard with a USB dongle. I hit delete to go into the BIOS to tinker around, and after 5 seconds, the keyboard stops working in BIOS, making me have to dig out a PS/2 keyboard and pull my HTPC out of the entertainment center just to tinker around in BIOS.

Wow, what a complete ramble. TL;DR:

1. Are my motherboard temps too high?
2. Is the motherboard increasing the CPU fan speed to alleviate the motherboard temps? (which wouldn't help)
3. Should I find another low profile HSF or should I move the HTPC?
4. Generally can you manually set fan speed in BIOS? (haven't yet looked deeply because of PS/2 requirement)


Best solution

May 26, 2010 12:44:17 PM

1. Temps are a bit high (those are idle, right?). What are your load temps? You can undervolt the CPU to help with heat management.

2. Either the motherboard is faulty and supplying more volts to the fan than it should, or the fan is faulty. I suggest you get another fan, run it at full speed on a different computer, and see what the rpm reads on Speedfan. If that same fan runs at a higher rpm when connected to the CPU fan header on your HTPC, then that suggests the motherboard is faulty. 7000 rpm???!!! Holy sweet Jebus! BTW, are you sure there's only one fan header? Usually there's a CPU_FAN 4-pin PWM header and then at least one 3-pin CHA_FAN header. You should be using the CPU_FAN header for your heatsink fan.

3. If you are still having heat issues, take a look at the Scythe Ninja Mini which is perfect for your case and can even run without a fan because it's right next to your 120mm exhaust:

4. Have you updated your BIOS? Wireless USB should work just fine in the BIOS... maybe a BIOS update would fix things. Anyway, Asus board usually have something called Q-Fan in the BIOS that controls fan speed. Settings are something like Off (full speed), Performance, Optimal, Quiet. That's what my current Asus board has so your might be different.
May 26, 2010 2:22:38 PM

1. Yeah those are idle temps. I ran Prime95 for about 10 mins, my Core went to about 47ish and Temp1/2 sat at about 51.

2. What strikes me as strange is it's a slow increase. By the time I get into windows and Speedfan open, my Fan RPM is around 4900. After about 5 mins its up to 6900.
I have triple checked, I truly only have 1 fan header. ASUS Motherboard image see for yourself. Only one fan header.

3. I have been researching some low profile coolers, but most that Ive seen suggest 65W CPUs, and mine is 95W. I assume it might mean I would just be warmer than whats reported, but its kind of a limb to go out on.

4. No I havent updated my BIOS yet.
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May 26, 2010 3:55:19 PM

I see two fan headers in that picture. The 4-pin PWM CPU_FAN header is on the top edge of the board next to the blue RAM slot latch. The CHA_FAN 3-pin header is just above the "GPU NOS" wording.

I just checked the Asus site... they've already released 10 versions of the BIOS. A lot of BIOS fixing is my guess. One of the releases mentions keyboard detection. Update to the latest (0906) and see if that fixes some of your problems with fan speed and keyboard detection.

Another good low-profile HSF is the Scythe Big Shuriken.
May 26, 2010 4:04:48 PM

That header is designed for some feature called GPU_NOS. I figured it was something for a GPU Fan, didn't think I wanted to mess with it.

I'm about to flash my BIOS but the BIOS isn't recognizing the USB thumb drive. And I really don't want to use a windows based flash program as I hear those are icky.
May 26, 2010 4:16:50 PM

Is your flash drive formatted FAT32?

If it's NTFS the BIOS won't see it.
May 26, 2010 4:18:06 PM

BTW, the "GPU NOS" is not referring to the header. If you look above the header it has "CHA_FAN" which stands for chassis fan. It's for a single case fan.
May 26, 2010 5:03:59 PM

Ah ok thanks, I ended up drilling some cut outs in the side of my entertainment center to help with airflow at the area of the 120mm fans.

Also right now I am tinkering around with Q-Fan. You were right it was set to Disabled, meaning the fan was set to 100% from the BIOS. Initially I had great success by setting it to enabled, starting my fan voltage to 4.0 rather than 5.0. The only thing that confuses me is it only has 2 other settings:

Fan Auto Mode Start Speed Temp - 25C
Fan Auto Mode Full Speed Temp - 55C

So I assume that if you have a temp > 25C that means it will actively adjust fan speed to react to increases in temperature.

With 55C being the top end, when it reaches 55C it will be 100%

So this stuff only becomes an option when I enabled Q-Fan. If Q-Fan is disabled, I simply get 100% all the time. But it is manually adjustable in Speedfan.

If I enable Q-Fan, I can't adjust the fan speed in Speed Fan, and it still slowly creeps back up to 6000+ RPM.

While posting this I did add a 80mm fan to the back as an intake blowing air across the motherboard. Maybe I should make it another exhaust?
May 30, 2010 5:48:38 PM

Best answer selected by cmcghee358.
May 30, 2010 5:52:09 PM

Just to follow up. I added 2 more 80mm fans to my HTPC case. I determined that the minimal clearance on each side was the biggest contributing factor. When the case temp increased the CPU fan spun up to cool the CPU.

I drilled 2 2" holes in my entertainment center at the location of the 120mm side fan, I drilled another 2" hole at the location of the PSU, and a 4th 2" hole in the rear where I added another 80mm exhaust fan.

I finished it up with an 80mm intake fan in the front drawing air in from the bottom.

Currently the fan speed stays around 2000-3000. With temps at about 40-42 across the board.

Next weekend I will be adding some IC24 TIM in the hopes of dropping another 3-4C and hopefully the fan will adjust under 2000 RPM.

Thanks for all your help boss. Especially with the BIOS and fan header :)