Blur is normal if you don't run the display at its native resolution.
What you want to do to is run the native high resolution and fiddle with the DPI settings.
Check the documentation for this option:
Option "DPI" "string"
This option specifies the Dots Per Inch for the X screen; for example:
Option "DPI" "75 x 85"
will set the horizontal DPI to 75 and the vertical DPI to 85. By default,
the X driver will compute the DPI of the X screen from the EDID of any
connected display devices. See Appendix E for details. Default: string is