Fan Control on Rendering PC

[smoosajee]

Hi,
I recently built a PC to handle all my day to day design work in addition to rendering. Per the suggestion of a friend, I got a Supermicro h8dg6-F motherboard with dual amd opteron CPU's to do heavy lifting on CPU renders.

I currently have two Noctua Noctua NH-U12DO Heatsinks in my PC, one on each CPU. These heatsinks keep my CPU's very cool (at rest, usually 18-20 degrees C, while rendering, never above 40 degrees C)

I also have 3 GTX 1070's for GPU rendering. I figured with both the GPU's and CPU's, I would need at least a few case fans to keep the thing cool. So in addition to the 4 fans that shipped with my heatsink (2 on each sink) I purchased 3 additional Noctua fans, the highest quality I could find.

Sometimes my PC is blissfully quiet, you wouldn't even know its on. Other times, the fans will randomly rev up to almost their max RPM, for no apparent reason. Additionally, when I go to do a CPU and even sometimes GPU render, the fans go to their max RPM (even though my system never comes close to going above 35-40 C on average).

After a lot of research, I thought this might be because I was using 3 pin fans and my motherboard manual recommends using 4 pin fans as those support automatic fan control. So I bought all new Noctua fans (4 pin PWM versions) and then installed them with low noise adaptors per each fan ( even on the 900 mm heatsink fans). I was hoping this would solve my problem but unfortunately it has not. When I go to do a CPU render, the fans go crazy and immediately go to around 1500-1600 RPM, which seems to be massive overkill to keep my Opteron's cool as according to the website their recommended temp is between 60-70C. Additionally, the fans are doing this for GPU renders even though my Nvidia cards already have fans built in that are cooling the cards just fine.

Long story short, I am desperate for a reliable way to throttle my fans so that my system stops being loud and driving me insane. I've researched a decent amount and most people seem to suggest setting the fan threshold in BIOS, or using an app like Speedfan. I've tried to set the threshold in BIOS, but I don't get any control over individual fan speed. I only get 4 fan speed modes (performance, high speed, balanced, and energy saving) - in addition to a readout of the current fan speed RPM's without any way to change them. I'm currently using balanced mode as that seemed to give the most bearable results.

I downloaded speed fan in the hopes of using that, but unfortunately it doesn't recognize any of my systems fans (regardless of whether they were 3 pin voltage or 4 pin pwm). So I wasn't sure where to begin with that. I would be forever grateful for any help! below is my system build:

1 x Supermicro h8dg6-F motherboard
1 x Samsung 850 EVO SSD
2 x amd Opteron G34 socket CPU's
64 Gigs of G.Skill Sniper Ram
1000w EVGA fully modular Power supply
3 x EVGA NVIDIA GTX 1070 GPU's
2 x NH-U12DO Noctua G34 Heatsinks (they ship with 3 pin voltage 90 mm fans, I also bought and swapped in the 4 pin PWM versions)
3 x Noctua NF-F12 PWM Cooling Fan (using as case fans)

 

[The_Staplergun]

I'm gonna suggest something that -might- work. I hope it does.

See if you can acquire a program called AI Suite. Don't change any settings in it. On the side theres a program called fan expert, it may work. It's one of the best fan control programs out there, and correct me if I'm wrong, it probably IS the best.
I'm pretty sure it only comes on Asus motherboards but I know some software works with other hardware. It's worth a shot and can help with that as it has ramp up and slow down timers and you can tune the fans and make a custom curve.

 

[k1114]

Ai suite is an asus software that only works on asus mobos. There isn't any software that will work with that mobo and since the bios doesn't have the option, I don't see any way except hardware. A fan controller that the fans plug into or adapters to the psu for no control but a constant speed.

 

[The_Staplergun]

Ok, I'm glad you clarified that. Thanks.

 

[Zerk2012]

Your saying system temp but you should be looking at the video card temps.
GPU renduring stresses the cards not the entire system. Cards get stressed more heat higher fan speed.

 

[smoosajee]

Your saying system temp but you should be looking at the video card temps.
GPU renduring stresses the cards not the entire system. Cards get stressed more heat higher fan speed.

I didn't put a lot of information about the cards because generally my system is much quieter when GPU rendering vs CPU renders. Usually, when I do a GPU render and have the cards at 100% load they are about 70-75C max (I have the cards on the default setting, no over clocking).

 

[smoosajee]

Ai suite is an asus software that only works on asus mobos. There isn't any software that will work with that mobo and since the bios doesn't have the option, I don't see any way except hardware. A fan controller that the fans plug into or adapters to the psu for no control but a constant speed.

That is kind of what I was afraid of. Do you have a recommendation for a specific fan controller that would be good in this situation, or will any decent controlling board do the job?

The reason I'd picked Noctua was because in my research people seemed to be getting good results with the low noise adaptors. The LNA definitely made everything a lot quieter, but it doesn't yield a constant speed – when I render the RPM's almost double. Just wondering if the best way for me to tell the machine something like "never let the fans go above 900 RPM" is with the fan controller or some other adaptor I'm not aware of

 

[Paperdoc]

Unfortunately you are trying to fight reality. Fans blow air, and air flow removes heat. Higher temperatures inside your case cause the system to request higher fan speed to achieve higher air flow. Of course, those higher speeds and air flow also mean generating more fan noise. You can NOT get more heat removal without getting more fan noise.

You have already done the most important thing to reduce fan noise in your system. You chose Noctua fans, which have a reputation for durability and higher air flow delivery at lower noise levels (for any particular fan speed) than most competitor products.

Most mobos have TWO different cooling control systems, although they operate in a very similar fashion. In each case the control loop has a temperature sensor to measure actual temperature of the item being cooled, a setpoint target for that temperature, and a means of manipulating the speed of the fan(s) plugged into that header so that the airflow they generate can bring the measured temperature to target. Although we all talk about "fan speed control", these systems really are TEMPERATURE control systems, and the only manipulate fan speed to achieve their goals. Most mobos have one system for cooling the CPU, and its basis is a temperature sensor built into the CPU chip itself. In your case, with a dual-CPU chip design, I suspect there are two of these systems, one for each chip, and each controls only the fan plugged into the FAN7/CPU1 or FAN8/CPU2 fan header. Then the mobo has at least one separate temperature control system for cooling the entire case interior, based on a different temperature sensor built into the mobo, and guiding the headers used for system fans. That one system may be governing all of the FAN1 through FAN6 headers - can't really be sure because the mobo manual is not specific at all. On p. 4-11, although it lists several temperature sensors, it also says the BIOS really only accesses and displays for you the two CPU temps and one "System Temperature", so maybe that latter is used for all those six case fan headers.

The case fan temperature control system will have some internal table of how to change the fan speeds according to what is measured for the System Temperature. Details are not provided. It may operate on the basis that one temp range calls one fan speed, and the next range up calls for a faster speed, etc., but there is no indication how many such steps there are in its strategy. It does give a clue (MAYBE) in telling us it looks at CPU temps in terms of three levels below an alarm upper limit. Since the documentation also describes four possible control options, it may actually use four slightly different tables to convert a measured temperature into a fan speed setting. Full Speed just uses full speed all the time, I guess. The other three appear to use progressively less fan speed (and airflow, and noise generation) for any given measured temperature.

I recommend you remove the "Low-Moise Adapters". That name sounds enticing. But what these items really do is add a resistor into the power feed to each fan so that it runs more slowly than the mobo header intended. What that can do is fight the automatic control system. The system sets a fan speed according to measured temperature, but the LNA added in makes the fan under-perform, so the system keeps on heating up. That forces the control system to raise the fan speed, destroying the dream of slower quieter fan. If you remove the LNA's and just concentrate on choosing which Speed Option to use in BIOS, that will get you closer to what you need. Those LNA'a really are intended for use only by people who are not using the mobo fan headers and the automatic control systems at all. They are used when the fans are connected directly to a PSU power output that can exercise no control, and thus the LNA is the only way to reduce fan speed.

I suggest also that you look a little more widely at what you expect. The case fans are supposed to respond to temperature inside the case on the mobo, whereas the CPU fans respond to different temperatures inside teach CPU chip. Your post compares fan performance only to the CPU temperatures, and ignores other temperature readings. For example, although the GPU systems have their own cooling controls, they discharge heat into the case interior, raising the System Temperature. This would require raising the speed of case ventilation fans even if the CPU chips' internal temperatures were not rising.

You may not have been aware that there are two or three fan speed (really, temperature) control systems operating. Your post does not indicate which fan(s) are speeding up at times - it appears you believe they all do the same thing in response solely to CPU temperatures. Re-examine more closely which fans are doing what, and which temperatures are involved, during these times. That may help you to configure the cooling systems better. One thing to look for is the possibility of making different choices for the CPU cooling and case cooling options. p. 4-11 of the manual does not make this clear. But maybe you can choose different options for the case fans versus the two CPU fans.