The TIE Advanced x1 is the first in a series of advanced TIE fighter designs.Darth Vader himself designed the prototype for his personal use. It retains the original "TIE ball" cockpit and laser cannons of the standard TIE Fighter, but the similarities end there. The wing struts, solar panels and rear hull are all newly developed for the TIE Advanced x1.
Upgrades to the TIE platform were not merely cosmetic. Vader's TIE featured exceptional speed and agility, roughly equivalent to that of the TIE Interceptor. Further, in a radical break from standard TIE philosophy, the TIE Advanced x1 was equipped with a deflector shield system. While not especially, strong, this shield featured a rapid recharge rate, allowing it to break from combat to recharge, and reengage at the pilot's discretion.
In yet another departure for Imperial fighter design of the time, the fighter was equipped with a hyperdrive, at Darth Vader's insistence. While not an exceptionally fast one and not well-suited for deploying the fighter to remote locations for attacks, it was useful as a method for a pilot to escape from a dangerous area, or, as in Darth Vader's case after the Battle of Yavin, to jump to an Imperial base when a suitable landing area (or Death Star, for that matter) was no longer available.
Vader's prototype was unique, but was used as the basis for the limited-run TIE Advanced x1. Produced in very small numbers and issued only to elite pilots, the TIE Advanced x1 was more than a match for nearly any fighter in space at the time. Its closest match in speed, agility, shielding, and firepower was the A-wing.
The TIE Advanced x1 is easy to confuse with other fighters in the TIE Advanced series. Most commonly, the TIE Avenger, flown by the player character in games like TIE Fighter, X-wing vs. TIE Fighter, and X-wing: Alliance, is referred to as a "TIE Advanced." This is certainly correct, as it is a craft with in the TIE Advanced series. However, its specific designation is "TIE Avenger," and is a distinct craft with little or no parts in common with the TIE Advanced x1. Among other differences, it features a completely different hull, quad lasers instead of twin lasers, a warhead launcher, advanced shields, and a more robust hyperdrive than the x1 model.