There's not a lot to go on here, and so far nobody has come forward to tell how well (or how poorly) it runs, but a new RUU has leaked out for the AT&T One X. The update brings the One X to version 1.85.502, and breaks all current rooting methods. It's a standard HTC RUU, so that means Windows only and the proper drivers need to be installed. Note that this may not be the final update version, and you may end up stuck with it if you flash it.
Anyone who gives this one a try should be sure to let the rest of us know about any changes or improvements. Grab it at the source link.