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 can find almost any hardware monitor chip connected to the 2-wire SMBus (System Management Bus (trademark belonging to SMIF, Inc.), a subset of the I2C protocol) and works fine with Windows 9x, ME, NT, 2000, 2003, XP, Vista and Windows 7. It works with Windows 64 bit too.
SpeedFan monitor temperatures from several sources. By properly configuring SpeedFan, you can let it change fan speeds based on system temperatures. When choosing parameters for the minimum and maximum fan speed, try to set them by hand (disable all the VARIATE FANs checkboxes) and listen to the noise. When you hear no noise from the fan then you can set that value as the minimum fan speed for that fan.
I suggest to use 100 as the maximum value, unless you hear a lot of noise from it, in which case you might reduce the maximum speed to 95 or 90. You can set, say, 60 as the maximum value and, sometimes, I myself set it that way. Consider that when the WARNING temperature is reached, the program sets the fan speed to 100, whatever maximum speed you selected. One last word should be said regarding the USE FAN x listbox.
SpeedFan can access digital sensors available on your pc. By acessing available hardware monitor chips, SpeedFan can show temperatures, voltages and fan speeds. SpeedFan can show S.M.A.R.T. data from almost evey hard disk too. Temperature sensors from almost every manufacturer are automatically detected and accessed. Usually, the only action you need to take is to rename the readings that SpeedFan found. If your hardware allows it and you properly configured SpeedFan, you can change fan speeds depending on system temperatures, thus reducing overall noise.
With the F2 key you can rename any reading found by SpeedFan. On the configuration dialog you can see the hardware monitor chips that were found, where they are located and sample readings. SpeedFan knows about a lot of different digital sensors and system bus. If you happen to see an unusually high temperature on this dialog, perhaps it is simply a disconnected sensor: something that the hardware monitor chip can monitor, but that the motherboard manufacturer didn’t use.
S.M.A.R.T. (or SMART) is a technology that allows the end user query the hard drive about its health and, usually, performances. SpeedFan can query those info for you. SMART reports, for example, if the hard disk has been used for too much time (thus reaching its expected end of life), or if it took too many attempts to start spinning, or even if too many read errors occurred.
This program is aimed at the power user. At those who know what they’re doing. I’ve known of no real problem caused by SpeedFan, but stuill use it cuatiously and if you have no idea of it then it is better to ignore it altogether.