Maps that use marker line and hash line symbols and that are very large scale have poor drawing performance.
This problem occurs because of how ArcMap's renderers retrieve and draw features.
When drawing features, ArcMap uses the spatial grid of the data. It accesses all the index grids that intersect the current extent, and then it draws all of the features that are indexed by these cells.
If the map is viewed at a very large scale or zoomed in significantly, ArcMap draws all of the markers of the marker line symbol for the layer, even though most of the data is outside the visible extent in the ArcMap layout window. It is the drawing of these unnecessary but not visible markers that causes poor performance.