In each 0.02 seconds:

[228853.564272] x86/PAT: Xorg:514 conflicting memory types AAAAAAAA-BBBBBBBB uncached-minus<->write-combining
[228853.564278] x86/PAT: reserve_memtype failed [mem aaaaaaaaaa-bbbbbbbbbb], track write-combining, req write-combining

In the direction of memory:
AAAAAAAA-BBBBBBBB: a 0x1000 size
aaaaaaaaaa-bbbbbbbbbb: range 0x0 to 0xfff

This error repeat each 0.02 seconds and slow down to halt all PC, not respond the keyboard and mouse, also not change the leds of keyboard, all system halt. (i view that the mouse change position any 3 or 4 pixel in each 10 second)

This error present and halt machine where:
* In the firefox have a very ground page
* In the firefox have a java shared with other app java
* Open firefox and virtualbox where request more amount of memory
* firefox with java apps (like facebook or google) in virtualbox
* Open two Xorg (like mix of xfce, blackbox, gnome, etc)

I have this machine:
Kernel: 4.2.5-1-ARCH (Archlinux always last updates to 4.2.5)
Release Date: 2015-11-09: X.Org X Server 1.18.0
Current version of pixman: 0.32.8
nvidia-xconfig:  version 304.131

This problem have since 6 month ago.