Created attachment 96624 [details]
dmesg excerpt, crash dump, and installed package report

Display freezes for several seconds, usually resumes.  During the frozen time, the mouse pointer still works, and changes icon appropriately.  Activity usually continues in the background, and is shown properly when the freeze ends.

Recently upgraded my vanilla kernel from 3.10.34 to 3.13.7 to see if this has been resolved.

Although the freeze can happen at any time, it happens more often when using Virtualbox VMs.

Desktop is KDE 4.12 w/ effects enabled.  Base OS is gentoo unstable.
Complete installed package report appended to the GPU crash dump attachment.

Highlights:
media-libs/mesa-10.1.0
x11-apps/mesa-progs-8.1.0
x11-base/xorg-server-1.15.0
x11-drivers/xf86-input-evdev-2.8.2
x11-drivers/xf86-input-keyboard-1.7.0
x11-drivers/xf86-input-mouse-1.9.0
x11-drivers/xf86-input-synaptics-1.7.3
x11-drivers/xf86-video-intel-2.99.910
x11-libs/cairo-1.12.16
x11-libs/libdrm-2.4.52
x11-libs/libva-1.2.1-r1
x11-libs/libva-intel-driver-1.2.2-r1
x11-libs/libX11-1.6.2