Created attachment 95520 [details]
log of boot

I recently added a R7 260X to my system.  While the card works with 3.13 its
supposed work much better with 14-rc.  This is not the case.  My system is
unstable without radeon.dpm=0 which was the default in .13.  

linux 3.14-rc6 (with an up to date arch, stable X and mesa-git (10.2) mesa 10.1
and 10.0 also show very similar problems.

When X started I did notice some corruption.  There are sets of two rectangles
about of a height of 2 or 3 mm, width of 25m or so with a second about a cm
below.  The often occurs in chomium especially when scrolling.  Runing the 
unigine-sanctuary or unigine-tropics demo/benchmark programs also produce the
above problems and eventually stall.