what is X11

I don't use it either but basically it allows you to run *nix software on your mac. Well stuff that is X-11 Compatible will run...

Press link.

Download blurb at the top describing it.

what speed is your computer? you may be fast enough to run it... if you're running 9.2.2 it should work fine... i run X on my iMac 400 and while it's not the fastest in the world, it works great for my use...

unless you need *nix compatability, which i'm guessing you don't, ignore X11.

pnw

X11 is a really awful old windowing system that is sadly still in use in the Unix world and has been kept at least semi-modern by loads and loads of "extensions" that enable it to do things it once wasn't able to do* (like font rendering, alpha blending, changing resolution on the fly, direct OpenGL support, etc.). Unfortunately, these extensions, added onto its original shoddy design, have had the effect of making it an incoherent, bloated mess.

"I think X Windows is brain-damaged and will fail."
-- Steve Jobs, summer 1987 Usenix conference. He was half right.

* Although X11 can "do" these things, it can only do them in a kludgy, haphazard, nonstanard manner.

For more information about X11, go here.