It can set your fan speed indeed, but on my iMac (early 2008 kind) it also disturbed global SMC behaviour, my CPU sensors looking suddenly like warming up to the top, so I uninstalled it.

Been using Fan Control since May 2008. To date, I have used it on an Early 08 MacBook and a Late 11 MacBook Pro 15. I wish it had more options and flexibility, but it has been useful and trouble free for me, and by reducing the temperature at which the fans kick in and the temperature at which they reach maximum, it has been a real help and overall both portables run over 10F cooler than without FC. FYI the way that FC monitors and adjusts the fans is different from Apple's default behavior. FC responds directly and immediately to temperature as read from the CPU/cores. Apple's SMC reads those temperatures, but also monitors system load. This is supposed to keep things cool by anticipating heat-up. So when you load Photoshop or any other app or game that puts a heavy load on your CPU, the fans should ramp up before the temperature actually increases, and then the speed is adjusted either up or down according to how much heat actually is generated.

The problem with Apple's default approach to thermal management is twofold. First, it relies on the BSD load monitoring (if you have iStat or Hardware Monitor it is shown as "load" and expressed as a decimal, e.g. .07, .44, 1.79, etc. This is a percentage of the total system resources and capability). The problem with that is this measuring and reporting of load was designed for single core systems, and on anything from Core Duo forward won't report accurately. IN particular, it will make the fans spin too fast in many cases. The other problem is the SMC won't lower the fan speed again until the load reported falls below a certain value (who knows what). Even if you quit the heavy duty app, or it is just idling, and the actual temp has already fallen way below a triggering level. Fan Control sets the fans directly according to the actual temp, without regard to load, or to percentage of CPU in use (which is a seperate stat). The Apple SMC also tends to be slow to start cooling (as well as slow to stop extra cooling as described above), I don't know why. I think it is also the BSD load reporting, since many times I know I am using massive amounts of CPU and RAM (confirmed by a look at the Activity Monitor, and the load reported in "top" is over 0.50) and yet the fans are still loafing around 2K rpm.

So, I unreservedly recommend Fan Control. I find it much easier to use than smcFanControl, which is also a good utility but not transparent like FC, and much safer than something like CoolBook, which mucks about at a very low level with your CPU internals. Just beware the issues about installation and removal (just manually trash the prefPane, and the FC Daemon folder, and perform an SMC reset, and that's that).

It's a great idea to help speed up your Mac's fan, however, I've done some looking and a lot of users have said by speeding up their fan's rates or making it turn on at lower temps, it's prone to make your fan burn out quicker..

Just a heads up!

you instal it once and you forget it, it takes care everything for you. completely automatic fan-speed control proportional to the temperature.

My fans started to get noisy as hell, just a few months after replacing them for that same reason.

I uninstalled Fan Control and not my MBP is silent again. Looks like they'd rather run at 2000 rpm than 3000rpm...

I have a silver MacBook from 2009, running 10.5.8, and my fan is constantly around 6200rpm. Sometimes the temp is around the high 80s (C), and other times it's not hot at all yet still running the fan. Right now it's at 86 C. I've tried various fan control things for when it's not overheating. This one, Fan Control, I can't find it anywhere once it's installed. It says it's installed in System Preferences, but there's nothing there that's new. Is it hiding in one of the sub categories or something, like Energy Saver or something? It's really annoying... plus my CPU has never been this hot...

Piece of crap, had to install cleanapp to uninstall it. get smcfancontrol much better.

I have dowloaded the file and then installed it using mac install or whatever but i cant get the actual fan control window with the bars and graphs to open.
Thanks

when i open fan control, the other fan say right fan is -1rpm, while the left fan is say 2769 rpm, i think the right fan is not working. my macbook model is Macbook MacBook2,1.

So for those who are wondering why the right fan reading is 0 or -1:

If you have a MacBook pro, do a hardware check, write down the error code if any, and bug Apple.

If you have a MacBook, no worries, your notebook has only one fan sitting in the middle. Thus the left fan is actually the one and only fan your Mac has, disregard the right fan reading.