I don't know if it's a testament to Samsung and their software developers, or to the OP's luck for flipping the right switches without knowing what they are for . . . and no insult meant to the OP.
I don't think RAPID activates itself without user intervention. But a user could "intervene" without understanding the result that would follow.
We've been all over RAPID and other Ram-Cache software like flies on a dead bunny-rabbit, nor will more posts and threads on the topic irritate me.
As long as your RAM has been tested, your system is stable and reliable, it is a helpful feature. The critics say that it "only improves benchmarks," but that's not really true. For an end-user who establishes "habits" in computing practice, it has positive benefits. And it is a way to leverage all that RAM that you thought you wanted, but which seldom gets full utilization.
I'm still trying to decide whether to buy Primo-CAche or Super-Cache for my computer(s) fitted with Crucial SSDs.
There is also a trick with a registry edit to increase the size of Windows' file-level caching. I rather doubt that it would have the impact of RAPID or the other programs.