View update using TTFonts in MicroStation V8.1
When Font Smoothing is turned enabled on your workstation, the time it takes to refresh/update/redraw a drawing with TTF text may increase substantially.
To verfity that this setting is indeed off, do a right-click on your desktop and pop to the Properties dialog. From there go to the Appearance tab and poke on the Effects button. Lastly ensure that the smooth edges setting is disabled.