The pentium II xeons ran from 350MHz to 450MHz depending on the model. They were slot processors (instead of socket).http://www.cpu-world.com/CPUs/Pentium-II/Intel-Pentium%20II%20Xeon%20450%20-%2080523KX4501M%20(BX80523KX4501M).html
-as fast or faster than anything else from 1997-1998 depending on the model.
-Good enough on paper to run windows xp (will run like *** though)
-can't run anything past windows xp
-is slow compared to every used processor I have in my house that I got for free in junkyards
-What else do you want to know? Be more specific. Is there something you had in mind?
We might be able to help more if you tell us your other system specs and what you want to use it for. Like o1die said, the more info you provide, the more responses you'll get.