iFreeMem

I'm running the demo of this little app, but not sure if it really makes a big diffrence, so don't know if i want to fork out for it.
Any one else using it, and what's the deal with inactive memory any way?
Sim

Inactive memory is memory that WAS being used but is not being used any longer. It sits in the incactive state until it needs to be called upon. I thought about getting that program, but as you noticed, it doesn't make a huge difference.

Yeah, apparently, the process of accessing the inactive memory slows a program down, but just after using iFreeMem, there is a slight slow down as well so can't really see the point. Cheers for the response.
Sim

Is that true that the cause of programs slowing down is due to converting inactive memory to free memory? I think it's a pretty neat little program, but is there a free alternative somewhere?