That’s exactly the kind of hardware that’d get a big a boost in performance by switching to Linux. Go for it! I have so many old machines that have essentially gained a second life when I installed Linux on them. You can’t go wrong with either an Ubuntu, Debian, or Fedora-based distro. I am not sure what 2Ghz requirement you’re talking about, but I’ve run Fedora on potato class hardware so I think it will be fine.
If you start getting used to Linux after a while, I’d actually suggest Arch because of how slim of a system you can achieve with it and how fast in general it usually is. Of course, if this is your first time using Linux definitely try out some of the friendlier distros first!