"FS2000 was released as a major improvement over the previous versions, and was also offered in two versions; one version for "normal" users, and one "pro" version with additional aircraft. Although many users had high expectations when this version arrived, many were disappointed when they found out that the simulator demanded high-end hardware; the minimum requirements were only a Pentium 166 MHz computer, although 400–500 MHz computer was deemed necessary to have an even framerate. However, even on a high-end system, stuttering framerate was a problem, especially when performing sharp turns in graphically dense areas. Also, the visual damage effects introduced in FS5.0 were disabled, and continued to be unavailable in versions after FS2000. While the visual damage effects were still in the game, Microsoft disabled them from the game's configuration files. Users can re-enable the damage effects through modifications. FS2000 also introduced computer controlled aircraft in some airports."