修改/etc/X11/xorg.conf
Section "Monitor"
Identifier "aticonfig-Monitor[0]-0"
HorizSync 60.0 – 60.0 #加入这一行，为刷新率
HorizSync 60.0 – 60.0
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"

Section "Screen"
Identifier "aticonfig-Screen[0]-0"
Device "aticonfig-Device[0]-0"
Monitor "aticonfig-Monitor[0]-0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1440×900" #加入这一行，为你显示器的最佳分辨率
EndSubSection

或使用命令aticonfig –resolution=0,1440×900 (安装了ATI的官方驱动后才有)
下载地址:
https://a248.e.akamai.net/f/674/9206/0/www2.ati.com/drivers/linux/ati-driver-installer-9-3-x86.x86_64.run
注意：只有2.6.X的内核才能安装

显卡3D加速测试命令
[root@localhost ~]# fglrxinfo
display: :0.0 screen: 0
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: Radeon X1300/X1550 Series
OpenGL version string: 2.1.8543 Release
[root@localhost ~]# glxgears
15733 frames in 5.0 seconds = 3146.436 FPS
15033 frames in 5.0 seconds = 3006.294 FPS
X connection to :0.0 broken (explicit kill or server shutdown).