This speeds up a much but also may cause inexact results. Especially after zooming when error is propagated. Please see ahgorithm descriptions that explains why I decided for solid guessing. Now you may choose range. Default is 2x2.
Larger range means faster calculation and less exact results.
By pressing '1' you may disable this feature. Sometimes calculations takes so much time so framerate should fall very very low. In this cases xaos automatically reduces details so animation is still quite smooth. You may control This feature by pressing 'T'. This lets you choose when such resolution lowering is possible.