AutoCAD 2010/2011/2012 DWG Format

[#1]

I had a DXF file with an external reference file inside, when showing in AutoCAD 2012, the external file appeared very 'dull' and blurry. But when I look at the same file in the new AutoCAD 2013, it shows very clear.. this puzzles me, and our clients are complaining about this quite often. 

Is there a setting I can change in 2012 version to make it (external file) clearer?

see below. The right hand side shows the external file (table and words) much better than the left.

[#2]

Sounds like it is the XDWGFADCTL  system variable,, set it to -90