Edit > Preferences > General > Anti-Aliased Artwork – uncheck for faster redraws.
Here is a write-up indexing the best features and why this version is still highly regarded. The Legacy of Adobe Illustrator CS6 index of adobe illustrator cs6 best
Adobe Illustrator CS6, released in 2012, represents the last perpetual-license version before Adobe switched entirely to the Creative Cloud (CC) subscription model. This report indexes the aspects of CS6: its critical system directories, top-performing tools, and essential file paths for power users. Edit > Preferences > General > Anti-Aliased Artwork