Any modern software like Rain/Waterfall?

[Gunslinger08]

Is there any modern software that does the same thing?

 

[Bateluer]

Cool 'n' Quiet for AMD chips, and EIST for Intel chips. They have to be built into the CPU though, so thats probably not quite what you were looking for. I don't think many programs like that exist any more, mucking around with the CPU processes/threads is foolhardy.

 

[Sunner]

Yes there is, the Win2K/XP kernel is one, Linux kernel another, and so forth.