In the X Window System, XFree86 Acceleration Architecture (XAA) is a driver architecture to make a video card's 2D hardware acceleration available to the X server.
In the VIA Accelerated Linux Graphics Driver, XAA is on by default, though acceleration of individual functions can be switched off as needed in the server configuration file.
Option "NoAccel" "TRUE"
This option is to disable the XAA hardware acceleration. It belongs to Section "Device".
In X.Org Server release 6.9/7.0, EXA was released as a replacement for XAA. EXA is regarded as an intermediate step to converting the entire X server to using OpenGL. To enable EXA acceleration, add options into Section "Device" as,
When EXA is enabled, it's recommended to set video memory larger than 64M in BIOS settings. And the result of dimension*bpp/8 should be no larger than 8192.Section "Device" Option "AccelMethod" "EXA" ...... EndSection