If your HTC One X is included on the list, head to the sourcelink to see the directions on installing Jelly Bean. Those who have installed the update say it makes the phone "blazing fast" and gives you a quicker app launcher and smoother home screens. The Quadrant Benchmark test of an HTC One X with the Jelly Bean update resulted in an incredible score of 7031. The AnTuTu score was 12,924, just under the Samsung GALAXY Note II and the HTC One X+.
Do we need to remind you that if you don't know what you are doing you could brick your phone? Should we tell you that if you brick your phone you will be SOL? Does it pay for us to suggest that if you want Android 4.1.1 on your HTC One X, you could simply wait for the official software update or buy the HTC One X+ when it launches? Ah, we didn't think so.
source: XDA via AndroidCentral (1), (2)