RAIN is not a good program. I was trying to OC my pentium 90 and decided to add Rain. Everythiing went fine (except the overclock ) I decided to keep it installed just to keep the CPU cooler. A few days later, my computer slowed WAY down! I figured it might be because of the OC and I wrote a post about it. People said I might have corupted the registry and suggested a format. I reformated and reinstalled (I still had rain). I restarted to finalize all my settings, and guess what? The computer STILL ran slow! I thought it might now be something acting up. I formatted again and re installed windows. I didn't install anything else and it ran perfectly. I slowly added programs, each time running a benchmark to make sure my comp wasn't running slower. As soon as I installed and opened Rain, the computer slowed down again. Removing the program fixed the problem. I personaly don't like Rain anymore because of this. I would suggest going with Waterfall or CPUIdle ANYTHING BUT RAIN!. I didn't try either of the other two out, but they (I hope) can't be any worse than Rain.
These programs only cool your idle temps. What's the point? If your idle temps are to the point that they need cooling, then your load temps are going to be too high also right?
The load temp is the big one, not the idle temp. I think cooling programs are an absolute waste of hard drive space and system memory. If you design your system to lower your load temps then your idle temps will fall also.