One of the reasons why I like Mandrake is because the whole distribution is optimized for a Pentium system. Since your Overdrive CPU is Pentium on the inside, Mandrake will make the best use of what it has to offer.
The key here is to pick and choose to achieve best results. Instead of installing KDE or GNOME, your X Window System should use a lightweight window manager like IceWM-Lite, the X WinCommander file manager and other lightweight tools that come with Mandrake. You'll also want to cut down the number of running services to a bare minimum. If you do that, and have enough RAM, you'll have a slow but usable X setup on that PC.
You are false data.