System Information
Operating system and graphics card

Dell E6530, 8GB RAM
AMD Quad, 12GB RAM (custom machine)

Blender Version
Broken: (example: 2.69.7 4b206af, see splash screen)

Version: 2.73 stable release

Worked: (optional)

Short description of error
[The same issues occur on both machines listed.]

Program has been sluggish since download.
Starts happening as soon as program launches.

>  Moving mouse around starts getting slower responses.
>  Cannot assign simple material to object.
>  Have lowered the tile size to 64 to combat it but doesn't help.
>  After two or three mouse clicks, doing anything, the system starts
    'Not Responding' then freezes altogether.

Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
[No .blend file necessary since application won't allow much progress]

I have returned to using 2.72b with no apparent issues.

Thank you for looking into this. I don't know if this pertains to the new viewport shader settings or maybe a python loop or something. I appreciate the help.