Please check to make sure you are running your external display at its native resolution so that you don't have blurriness from scaling the image up or down.
For the local display - what is the native display resolution? if it is high resolution display (say 1920x1080 or higher), then what you are seeing may be a consequence of applications that are not designed for high res displays being "scaled up" by the operating system.
There are known issues with some legacy applications that were not written to be "Hi DPI aware" - these applications assumed they would be run on a certain resolution screen and thus the icons, text layout, etc are all tuned for that resolution (fixed number of pixels). If they were rendered at their native size in pixels, icons and stuff would look tiny; maybe pages wouldn't lay out correctly - so Microsoft offers a "fudge factor" to upscale these old apps... But that doesn't always work and it may make things blurry.
See these article for more information:
How Windows 8 scaling fails on high-PPI displays - The Tech Report - Page 1
High-PPI support in Windows 8.1: still not so great - The Tech Report
Sadly, the really nice hi res display that looks so great in Firefox or Internet Explorer and while editing photos... doesn't look so nice when fixed DPI apps wind up scaled up to a blurry mess.
Here is an article on how to check your DPI settings in Win 8.1: