Make your PC's fans quieter with Speedfan

The download link is quite difficult to spot (it’s a blue link titled ‘Speedfan 4.40’, just below the Download heading). If the File Download Security Warning dialogue box appears, click Save and then choose a location for the downloaded file. Firefox users should click Save File to save the download to Firefox’s default download folder. Now locate and double-click the ‘installspeedfan440.exe’ you have just downloaded.

Signal your acceptance of Speedfan’s licence terms by clicking ‘I agree’, and work through the installation wizard, accepting all of the defaults (unless you have good reason to do otherwise) and clicking Next at each turn. At the last dialogue box, click Close. Speedfan should launch automatically but, if it doesn ’t, it can also be found in the Speedfan program group under All Programs from the Start menu.

This is the opening screen of Speedfan. The program will spend around a minute interrogating the PC’s internal fans, temperature sensors, hard disks and so on and present a summary on the Readings tab. On our first test PC, for example, it found a graphics processing unit (GPU) running at a temperature of 68C and two hard disks measured at 43C and 41C. It has also detected the two cores of our PC’s dual-core processor, gauging their running temperatures at 31C and 32C respectively. At this point, your PC is still in control of its own fans and, as such, everything remains safe. However, from this point on we will be working to adjust the fan speeds and, as a final warning, there is a risk of causing permanent damage to your PC.

One trouble with Speedfan is that the information it displays is only as useful as the details provided by the PC. Our first test PC was not able to supply Speedfan with information about the fans, so there wasn’t much more we could do. However, this second PC (which is more modern) supplies detail about its fans, which Speedfan displays on its opening screen. However, it’s not clear which of the fan speeds, listed as percentages, relate to which component. Take this as another reminder that Speedfan is a tricky tool to use and how (or indeed if) to proceed from here will depend on what’s displayed on this opening screen.

We are going to stick with our second test PC and try to make sense of some of the labels here. Now click the Configure button. Now the Fans and Speeds tabs in turn. With any luck, the labels on one will match the other. In other words, if an entry is labelled ‘CPU1 Fan’ in temperatures, you would hope to find a matching label under the Fans tab. The idea is that the Temperatures tab is used to specify maximum and minimum temperatures for the various components while the Fans and Speeds tabs let you control fan speed to achieve this (potentially reducing noise). If all the labels match, feel free to skip to Step 7.

However, on our test PC there is no match. So, we know that our test PC has several fans but we do not know to which components they relate. There are three ways to find out but each has its flaws. You could attach a variable-resistor control to each fan inside the PC, which can slow a fan to see which reading changes in Speedfan. Speedfan can be used to switch off individual fans, although to do this risks damaging the processor if its fan is switched off for more than a few seconds. The way many PC engineers deal with this is to use a finger to gently slow a fan as it speeds; this will affect the reading sufficiently for you to discover which fan it relates to but – and there should be no misunderstanding here – this involves touching components inside the case while the PC is running and is potentially dangerous, both to the PC and you. Only the most experienced users should consider this. Should you manage to tally the fans with the correct components then use the F2 key on the entries under the Fans and Speeds tabs to edit the labels.

The next step is to set how hot each component can get before Speedfan issues an alert or takes cooling action. Here we have selected the processor (appropriately labelled ‘CPU’) on the Temperatures tab and used the controls at the bottom to set a Warning (maximum) heat of 60C and an ideal (Desired) temperature of 40C. These are not necessarily the figures you should use: check your PC’s documentation or use Google to research how hot each component can safely run. At the moment, though, we have still not done anything to adjust fan speeds – and with good reason. Click OK to return to the main Speedfan screen.

Spend some time watching the temperature readings on the right-hand side to see just how high or low they get. If a particular reading goes over the Warning level set in the previous step then Speedfan will alert you by placing a flame icon next to it. If this happens a lot, do NOT reduce the fan speed. However, if the figure remains in the safe zone (green tick) or even below the Desired warning (down-pointing blue arrow) for long periods, then it’s probable that the speed of any fan(s) associated with this component can be safely reduced.

To do this, click the Configure button followed by the Speeds tab. Now click to select a fan and set the Maximum Speed fan lower than 100%. Start with a 5% reduction (to 95%) and gradually work down. Each time, repeat Step 8 to see the effect the reduced fan speed has on the particular component’s temperature. It can be a long process of trial and error to find the ideal settings but it’s important to work slowly, otherwise you risk components overheating and becoming damaged.

Finally, it should be obvious just by looking at the application window that there is a lot more to Speedfan. We don’t have enough space here to go into sufficient detail on all the other features, so we recommend reading through the FAQ page of the Speedfan website for more insight. However, for a bit of help analysing the warmth of your PC’s components over time (which will help with Steps 8 and 9), click the Charts tab and use the tickboxes to plot a graph of the temperatures.