speed up video card of T41

Mine is radeon M7500.
And in my xorg.conf, I have:
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Section "Device"
Identifier "Configured Video Device"
Boardname "ATI Radeon"
Busid "PCI:1:0:0"
Driver "radeon"
Screen 0
Vendorname "ATI"
Option "MergedFB" "off"
Option "AccelMethod" "EXA"
Option "EXANoComposite" "false"
Option "AGPFastWrite" "On"
Option "FBTexPercent" "50"
Option "MigrationHeuristic" "greedy" # the most effective option
Option "DRI" "true"
Option "GARTSize" "256"
Option "AGPMode" "4"
Option "Colortiling" "On"
EndSection
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