What is speedfan?

The genuine speedfan.sys file is a software component of SpeedFan by Almico.
Speedfan.sys is a system driver that belongs to the SpeedFan application, a program that lets users monitor system temperature and manually adjust speed settings for the heatsink fan. A driver is a software program that provides communication between the hardware and the software components of a system. This is not an essential Windows process and can be disabled if known to create problems. Speedfan was originally written by Alfredo Milani Comparetti and released in 2001 for the Windows platform. Its features include monitoring S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) readings for EIDE, SATA and SCSI hard disks, in-depth online analysis of the S.M.A.R.T. data to a database with statistical models of hard disks.

SpeedFan stands for SpeedFan Device Driver

Speedfan.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc. The free file information forum can help you determine if speedfan.sys is a Windows system file or if it belongs to an application that you can trust.

Run a free scan to check for speedfan drivers in need of updating

Speedfan.sys file information

The process known as SpeedFan Device Driver or SpeedFan (version x64 Driver, x32 Driver) belongs to software Windows (version 2000 DDK driver) or SpeedFan - Hardware and SMART Monitor by Windows ( (version 2000 DDK provider) or Almico Software.

Description: Speedfan.sys is not essential for Windows and will often cause problems. The speedfan.sys file is located in the C:\Windows\System32 folder. Known file sizes on Windows 10/8/7/XP are 5,248 bytes (89% of all occurrences), 24,184 bytes or 4,096 bytes. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The program is not visible. The service has no detailed description. The file is not a Windows system file. speedfan.sys appears to be a compressed file. Therefore the technical security rating is 38% dangerous, however you should also read the user reviews.

Uninstalling this variant: In case of any problems with speedfan.sys, you may want to do the following:
  1) uninstall the associated program (Start > Control Panel > Uninstall a Program > SpeedFan - Hardware and SMART Monitor)
  2) search the support area on the Almico website.

Recommended: Identify speedfan.sys related errors

If speedfan.sys is located in a subfolder of C:\Windows, the security rating is 29% dangerous. The file size is 28,664 bytes (72% of all occurrences), 14,104 bytes or 25,280 bytes. The program has no visible window. It is digitally signed. There is no detailed description of this service. Speedfan.sys is not a Windows core file. speedfan.sys appears to be a compressed file.

Important: Some malware camouflages itself as speedfan.sys. Therefore, you should check the speedfan.sys process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

It's monitors the Temp. of your computer..
Speedfan.sys is the system service for Speedfan.exe, a CPU and system fan monitoring/management program.
    (further information)
SpeedFan is an hardware monitoring software that is able to change fan speeds according to system temperatures. SpeedFan can read S.M.A.R.T. values (and temperatures) from your hard disks and change the FSB speed.
  Tony   (further information)
Temperature monitoring software
I was use it for a ATI radeon graphic card fan. 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 supports SCSI disks too. SpeedFan can even change the FSB on some hardware (but this should be considered a bonus feature). SpeedFan can access digital temperature sensors and can change fan speeds accordingly, thus reducing noise. SpeedFan works fine with Windows 9x, ME, NT, 2000, 2003, XP, Vista, Windows 7, 2008, Windows 8 and Windows Server 2012. It works with Windows 64 bit too.
When you uninstall speedfan using uninstal.exe, some part of the program are not removed. Speedfan.sys is one of them. So don't forget to manualy remove it. in system32 folder (use search fonction)

Rating chart

Summary: Average user rating of speedfan.sys: based on 6 votes with 6 user comments. 2 users think speedfan.sys is essential for Windows or an installed application. 4 users think it's neither essential nor dangerous.

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Best practices for resolving speedfan issues

A clean and tidy computer is the key requirement for avoiding problems with speedfan. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the speedfan.sys process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

speedfan.sys [all]