SpeedFan is a free, but extremely powerful and customizable sensor monitoring and fan control utility that works with a huge range of motherboards. Our comprehensive guide walks you through the complex configuration and allows you to unlock the full power of this enduring software utility, a favorite of SPCR for years.
July 2, 2012 by Lawrence Lee
As fans are responsible for the vast majority of noise generated in modern PCs, fan control is a vital feature in the realm of quiet computing. The various chips and processors inside a computer must be cooled, but more often than not, the fans tasked with the job are run at speeds much higher than necessary. In olden times, fan control simply wasn’t offered and all fans operated at maximum full speed. Enthusiasts looked far and wide for low speed replacements or resorted to modifying fan cables with resistors and altering molex connectors to adjust the voltage drop, methods now considered old hat.
Today, all modern motherboards have some type of control built in with advanced models offering three or more controllable headers. Because of this, physical methods to adjust fan speeds are on the wane. Hardware fan controllers can be purchased but with motherboard control and the availability of low speed fans, they typically aren’t bothered with unless the number of fans involved is extreme; they’re also limited in functionality, offering only manual control.
Dynamic control can often be customized right in the BIOS/UEFI and in software so the experience can be tuned properly for real operating conditions. Most of the major motherboard manufacturers ship their own fan control and temperature monitoring software with their boards, though few have impressed us over the years. Asus’ latest implementation of their Fan Xpert software was the best we’ve seen so far and certainly the prettiest.
That being said, our favorite fan control utility is still SpeedFan, a free application that’s been around for over a decade. Developed and maintained by an Italian IT professional by the name of Alfredo Milani Comparetti, it’s currently on version 4.46. The description of the program on the website sums it up pretty nicely:
"SpeedFan is a program that monitors voltages, fan speeds and temperatures in computers with hardware monitor chips. SpeedFan can even access S.M.A.R.T. info and show hard disk temperatures… SpeedFan can access digital temperature sensors and can change fan speeds accordingly, thus reducing noise. SpeedFan can find almost any hardware monitor chip connected to the 2-wire SMBus (System Management Bus… and works fine with Windows 9x, ME, NT, 2000, 2003, XP, Vista and Windows 7."
While it sounds like a simple utility, it has a rather Spartan user interface that hasn’t changed much since its inception. Because it isn’t designed with a specific motherboard or line of motherboards in mind, it isn’t fully functional in its default state. To a novice, this may seem intimidating. The purpose of this guide is to walk you through the process of configuring SpeedFan to work properly and point out its main features and how to utilize them effectively. Hopefully this will give you greater control over how your system sounds or possibly even an alternative to purchasing quieter fans or a dedicated fan controller.
As the SpeedFan website states, "This program is aimed at the power user. At those who know what they’re doing." Setting fans to spin too slowly or to stop completely can cause overheating and possibly permanent hardware damage — please excercise caution when using SpeedFan.
Test System Configuration:
For this guide, we’ll be using the Asus P8P67 Pro as the example. The rest of the hardware in the system is not really important.
Our test motherboard with fan headers highlighted.
Before starting we suggest noting the names and locations of the board’s fan headers and then plugging in a fan for each, preferably with models of differing speeds to easily differentiate them. It’s also advisable to disable fan control in the BIOS/UEFI while configuring SpeedFan so the fans will run initially at full speed.
If this is your first experience with SpeedFan, the first thing you’ll notice is its functional, rather than aesthetically pleasing UI. Compared to the various fan control software utilities provided by motherboard manufacturers, SpeedFan has a very bland look consisting mostly of black text on a grey background.
SpeedFan, main screen. Problem/mystery sensors highlighted.
The main screen consists of a log box, a CPU usage meter, and reports sensor readings for fan speed, temperature, fan control, and voltage. SpeedFan automatically gives each sensor a label, but it’s never completely accurate. Some of the labels are incorrect while some sensors are completely erroneous, especially the voltage readings, e.g. the "+12V" sensor running at 6.86V.
The temperature sensors labeled "Core 0", "HD", and "GPU" can be trusted as they are produced independently by other components, in this case the CPU, hard drive, and graphics card, respectively. None of the fan controls worked by default, except for the GPU Fan control. Support for ATI/AMD graphics card was added recently (the fan speed sensor reads 0 RPM because our test video card doesn’t report fan speed).
Some questionable temperature and fan sensors can be identified immediately (highlighted in the screenshot above). The board we used has four fan headers, but a fifth fan was reported, "Aux2". There was a "CPU" temperature that made no sense, staying at a constant -60C. Also notable were the three "SMIOVT" sensors which reported the same value as "AUX". Part of the configuration process is figuring out exactly what these mystery sensors are.
In the "Info" tab, there is an option to download pre-configured settings for your motherboard which could save you a lot of time. This functionality requires you to sign up for an account at the SpeedFan website. There’s no charge for joining and you also get access to the latest beta version, which may work better on your particular board than the official build, particularly if it’s a newer model.
Once you’re logged in, enter your motherboard model and choose from a list of user-uploaded configurations. If you’re using a fairly new board, this is usually a shot in the dark, as the database is mostly filled with older models. Users can’t upload configuration files for a board that isn’t listed and it doesn’t appear until someone requests it via e-mail. It’s then checked and manually added, presumably by the site admin. More often than not, you’ll have to take matters into your own hands and configure it yourself.
The Configuration Process
The fan control and monitoring utilities provided by motherboard manufacturers are rarely as functional as SpeedFan, but they can give you some important information as they are configured for specific motherboard models.
With Asus’ PC Probe running side by side with SpeedFan, we can identify some of the fan and temperature sensors. If you don’t have a second utility to compare SpeedFan’s readings, stop each fan momentarily by pressing on the hub and note which fan speed sensor drops to zero.
If there are temperature sensors reporting the same value (like "System" and "SMIOVT" in the example above), stress the system with something like Prime95. This will heat up different portions of the board by differing amounts. If the sensors in question are indeed reporting different temperatures, the values will start to differentiate.
In the Configuration menu, start renaming the sensors that you’ve corroborated. This is a feature most beginners miss as it’s not particularly obvious. Click on a label and press F2, the same renaming shortcut key used in Windows Explorer. If you’d like to hide sensors on the main screen, uncheck the boxes to the left. You can also reorder the sensors by dragging them. In the Fan tab, make note of the chip name for the fans, in this case, "Nuvoton NCT6776F".
The next step is to enable the fan controls, which often don’t work by default. In the "Advanced" tab, select the controller chip for the fans in the drop down menu. The "PWM modes" determine how the fans are controlled. In this case, "Smart Fan IV" is code for BIOS/UEFI control. Change all of them to "Manual" (sometimes it will be called "Software control") and remember to check the "remember it" box in the bottom right hand corner for each PWM mode so the setting will stick.
Now that we’ve renamed the fans and enabled fan control, it’s time to determine which control is tied to which fan (note: the GPU fan control worked right out of the gate so no trial and error was necessary). Set them all to zero and check which fans slow down or turn off completely. In our case, both Chassis fans stopped, and the CPU fan dropped from about 1200 RPM to 800 RPM.
The inability to shut down a fan entirely is almost always a sign of PWM control. The range of control varies depending on the board and for the P8P67 Pro, the lower limit is unusually high. It’s also a good idea to swap 3-pin and 4-pin fans when testing PWM fan headers as some do not support voltage control at all, forcing 3-pin fans to run at full speed no matter what. This may be relevant for your overall fan control strategy.
After playing with the fan controls, we established that both Chassis fans are tied to the same control, so we edited the labels appropriately. Now, we still have to make sense of those wonky temperature sensors.
The Configuration Process (Continued)
One of SpeedFan’s most under-used features is its charting ability. In the "Chart" tab, you can pit the various sensors against one another, seeing how they change over time. We graphed the temperature sensors that were puzzling us, including "System" which correlated to what PC Probe’s identified as the "Motherboard" sensor (we wanted to know exactly where "Motherboard" was located). After going through the first few steps of configuration, we also noticed that all the "SMIOVT" sensors reported the same value, so we decided to discard two of them for being redundant.
When identifying temperature sensors manually, it’s helpful to heat the system up first so that differences can be more easily observed. We ran Prime95 for about 15 minutes until the temperatures stabilized, then placed a fan over different portions of the board to see if any of the sensors would react. "System" and "SMIOVT4" dipped a similar amount when the fan was cooling the PCH heatsink. "SMIOVT4" seemed to be more erratic so we decided it would be disabled in favor of "System". Moving the same fan over the RAM caused "AUX" to drop, so it appears there’s a sensor near the DIMM slots which is a nice bonus.
We also noticed that the "CPU" reading in PC Probe was always within one degree of "Core 0" (Core 0 and 1 are sensors generated by the processor itself), so all the fan, speed, and temperature sensors are now sorted out. We’ll switch our focus to setting up automatic fan control using custom parameters. Check the "Automatic fan speed" box and go back into the Configuration menu.
The sensors in the Temperature tab are expandable, allowing you to pick and choose which fans will react to them. Above we’ve set the CPU fan to respond to the CPU temperature, the GPU fan to the GPU temperature, and the Chassis fans to the hard drive temperature. The fans in question will speed up whenever the "Desired" temperature is exceeded and at the "Warning" temperature, it will override your settings and run the fan at 100% to ensure overheating doesn’t occur. If you click the "Show in tray" box at bottom right, that temperature reading will be displayed on the SpeedFan icon in the system tray.
In the Fan tab, set the desired minimum and maximum values for each fan, and check the "Automatically variated" box.
In the graphs above, you can see SpeedFan in action. Prime95 is run and the CPU temperature spikes. Shortly after, the CPU fan speed starts to ramp up (note: the fan speed graph was created a few seconds after the temperature graph, so it’s shifted toward the right, making the reaction time seem a little slow).
Refining Fan Control Further
For most users, the configuration process we’ve outlined is satisfactory but if you want even more control, there are extra options available to customize fan behavior further.
By default SpeedFan alters fan speeds in increments of 10%, but this can cause jarring changes in the noise level when the fan ramps up. In the "Options" tab, changing the fan speed delta to a lower value will create a smoother ride but will also effectively reduce reaction speed. For example, setting it to 1% will create a very gradual ramp up in speed but it would take a few minutes for it to make its way from 0% all the way to 100%.
In the Fan Control tab, check the "Advanced fan control" box to create a customized profile with the ability to adjust the entire fan speed curve for each fan. Click "Add" and give your controller a name (in our case "Test"), select a fan from the drop down menu and add the temperature that you wish to define its speed. A fan speed/temperature graph will appear on the right side with numerous, movable data points. Note: using this feature will override any other settings that have been configured.
In order for SpeedFan to work properly, it has to recognize the chips used for fan control and the temperature and fan speed sensors. This means that SpeedFan might simply be incompatible with your motherboard, particularly if it’s a newer model, at least for the moment. When we reviewed our test motherboard, the Asus P8P67 Pro, back in January of 2011, fan controls weren’t even listed on the main screen. It took a few months before SpeedFan was updated with support for the P8P67 Pro.
As we mentioned earlier, SpeedFan gathers some data directly from components like the CPU, GPU, and hard drive. This information is refreshed every three seconds creating a problem for users who prefer to let their hard drives sleep when they’re not being used. With SpeedFan running, this isn’t possible as it is constantly polling each and every hard drive, keeping them awake.
Finally, in Windows 7 and Vista, loading SpeedFan causes Windows to issue a security notification before allowing it to run; the only way to get rid of this prompt is to disable UAC, one of Windows’ biggest security features. It’s not a huge issue if you only start SpeedFan once on boot-up and leave your system on, or put it to sleep rather than turning it off completely, but it’s still rather annoying. Most other utilities, including those provided by motherboard manufacturers, don’t have this issue unless used on an account without Administrative privileges.
The UAC prompt can be bypassed by using the Task Scheduler to start SpeedFan at login with the "start with highest privileges" option enabled. Thanks to one of readers, sunrunner20, for the tip.
SpeedFan isn’t the prettiest or easiest application to use, making it rather daunting for novice PC users. The biggest drawback is it often takes a lot of work to properly configure. However, once you invest the time (assuming you have a compatible motherboard), you’ll wonder how you lived without its incredible functionality and flexibility for so long.
It pulls data from additional sources (CPUs, GPUs, hard drives) so you don’t need extra monitoring programs running simultaneously to keep track of everything. Different fans can be configured to respond to different temperature sensors, something we’ve only seen on a handful of Intel boards like the DZ77GA-70K, and even then it’s only at the BIOS/UEFI level. Its highly customizable and incredibly powerful nature is unmatched by the competition and as a bonus, it’s also free, lightweight and regularly updated with more features and better motherboard support.
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