BLULOO  Buy new hardware? Want to reinstall your registered coolbook app?

The developer will tell you you're out of luck.

Neat little app but the dev says registration is only good for a specific machine.

You have to pony up more $$ for another license.

Lame policy for an otherwise useful app.  
(Version 2.14)

MHOLLIDAY84  My Macbook Air would always get really hot, and the video would start skipping when watching shows on ABC.com. With Coolbook, I was able to reduce the temperature of the core so that it wouldn't shut down and mess up my stories. used 0.9 V for all except 1600 MHz, for which I used 0.95 V. This software did exactly what it was supposed to.

I have a feeling that the reason some others didn't get as good of results as I did, is that they either don't know how to use the software, or they don't have their laptop on a flat surface. Remember that temperature transfers fastest from solid to solid vs. solid to air. My in-table for instance acts as a heat sync.  
(Version 2.14)

PEN_SQ  The 2.13 update is severely broken on my 2007 white MacBook (with i950). The first hint is when it is required to redo registration. After that, my voltage settings were lost. After rediscovering and entering the voltages, I didn't see Coolbook do anything useful with them.

I uninstalled and went back to version 2.12.   
(Version 2.13)

MICKFISH  I've been using CoolBook for a couple of weeks & I'm very happy with it. Straightforward & clearly explained. Did exactly what it said it would with the minimum of fuss & effort - what more could you want? Worth the money? Definitely. Can't really answer for stability but I'm pretty confident judging by results so far.  
(Version 2.12)

SAMPLER  CoolBook does much more than fan control. It can be used to decrease voltage, at no cost to processor speed, and thus it can reduce power consumption and heat. It looks like a must for the new MacBooks. See:

http://www.edn.com/blog/400000040/post/1890037389.html  
(Version 2.10)

HYBSTER  You should be aware that the author of the program insists on a strict "one machine" license, you will only be able to use this with one computer. If you upgrade, you will have to pay again. Stupid policy? Up to you...

"The license is for one computer only."

-Magnus Lundholm  
(Version 2.9)

HYBSTER  You should be aware that the author of the program insists on a strict "one machine" license, you will only be able to use this with one computer. If you upgrade, you will have to pay again. Stupid policy? Up to you...

"The license is for one computer only."

-Magnus Lundholm  
(Version 2.9)

DRDUL  Great app! Installed this on my Mac mini (FWIW, my settings are 1670 MHz/0.95 V and 2004 MHz/1.00 V). Temperatures used to hit 70 degrees Celsius for no apparent reason, and now remain in the mid-40s.  
(Version 2.9)

JKAHAN  Excellent product. I just installed it on my Macbook Air and no longer have heat or core shutdowns. Search the posts on macrumors for "underclock" and there is a good thread comparing everyone's coolbook settings.

The GUI could use some work though....  
(Version 2.8)

THANAR  Looks like Coolbook throttling is broken under newest Mac OS X 10.5.2, although it used to work fine under 10.5.1.  
(Version 2.6)