High cpu usage with compiz

[Aniruddha <mailing_list@orange.nl>]

I would like to use  compiz. Unfortunately this is problematic since my
system lags because of high (50%) cpu spikes. 3d acceleration is
working. Is there anything I can do to solve this?

CPU
> Intel(R) Core(TM)2 Duo CPU     E8400  @ 3.00GHz

Gfxcard
> ATI Technologies Inc RV670PRO [Radeon HD 3850]

xorg.conf
> ### This file was generated by xac v0.6_pre3
> 
> Section "ServerLayout"
> Identifier "XAC Configured"
> Screen 0 "Screen0" 0 0
> InputDevice "Mouse0" "CorePointer"
> InputDevice "Keyboard0" "CoreKeyboard"
> EndSection
> 
> Section "Files"
> ### Multiple FontPath entries are allowed (which are concatenated
> ### together as well as specifying multiple comma-separated
> ### entries in one FontPath command (or both methods)
> ### 
> ### For X Font Server support, uncomment this and comment the
> ### other FontPaths. (This is not required for most configurations)
> # FontPath "unix/:-1"
> 
> FontPath "/usr/share/fonts/misc"
> FontPath "/usr/share/fonts/default/ghostscript"
> FontPath "/usr/share/fonts/dejavu"
> FontPath "/usr/share/fonts/75dpi"
> FontPath "/usr/share/fonts/ttf-bitstream-vera"
> FontPath "/usr/share/fonts/corefonts"
> FontPath "/usr/share/fonts/100dpi"
> FontPath "/usr/share/fonts/Type1"
> EndSection
> 
> Section "Module"
> Load "extmod"
> Load "dbe"
> Load "record"
> Load "glx"
> Load "type1"
> Load "freetype"
> # Load "dri"
> EndSection
> 
> Section "ServerFlags"
> Option "blank time" "10" # 10 Minutes
> Option "standby time" "20" # 20 Minutes
> Option "suspend time" "30" # 30Minutes
> Option "off time" "60" # 60Minutes
> ### Uncomment so X doesn't fail when no mouse is available
> # Option "AllowMouseOpenFail" "true"
> ### Enable this option if X should not change resolutions
> ### This is useful if mode changing corrupts the X Server
> # Option "DisableVidModeExtensions" "true"
> EndSection
> 
> Section "InputDevice"
> Identifier "Keyboard0"
> Driver "kbd"
> ### Check /usr/share/X11/xkb/rules/xorg.lst for available models
> Option "XkbdModel" "pc105"
> ### Check /usr/share/X11/xkb/symbols/ for available layouts
> Option "XkbLayout" "us"
> Option "XkbOptions" "compose:rwin"
> EndSection
> 
> Section "InputDevice"
> Identifier "Mouse0"
> Driver "mouse"
> Option "Device" "/dev/input/mice"
> Option "Protocol" "auto"
> 
> ### Set driver options:
> ### No options set!
> 
> ### Unset driver options:
> ### No options unset!
> EndSection
> 
> Section "Device"
> Identifier "Card0"
> Driver "fglrx"
> ### Configured ATI Radeon Open Driver at PCI Bus ID:
> # BusID "PCI:5:0:0" 
> EndSection
> 
> Section "Monitor"
> Identifier "Monitor0"
> UseModes "Modes0"
> ModelName "BenQ G2400W"
> Option "DPMS"
> Option "ReducedBlanking"
> HorizSync 31-94
> VertRefresh 50-85
> EndSection
> 
> Section "Modes"
> Identifier "Modes0"
> ### # 1920x1200 59.95 Hz (CVT 2.30MA-R) hsync: 74.04 kHz; pclk: 154.00
> MHz
> Modeline "1920x1200"  154.00  1920 1968 2000 2080  1200 1203 1209 1235
> +hsync -vsync
> ### # 720x400 59.55 Hz (CVT) hsync: 24.83 kHz; pclk: 22.25 MHz
> Modeline "720x400"   22.25  720 744 808 896  400 403 413 417 -hsync
> +vsync
> ### # 256x341 59.09 Hz (CVT) hsync: 21.09 kHz; pclk: 6.75 MHz
> Modeline "256x341"    6.75  256 264 288 320  341 344 354 357 -hsync
> +vsync
> EndSection
> 
> Section "Screen"
> Identifier "Screen0"
> Device "Card0"
> Monitor "Monitor0"
> DefaultDepth 24
> 
> SubSection "Display"
> Depth 8
> Virtual 1920 1200
> Modes "1920x1200" "720x400" "640x480" "640x480" "800x600" "720x400"
> "720x400" "640x480" "640x480" "800x600" "256x341" 
> EndSubSection
> 
> SubSection "Display"
> Depth 16
> Virtual 1920 1200
> Modes "1920x1200" "720x400" "640x480" "640x480" "800x600" "720x400"
> "720x400" "640x480" "640x480" "800x600" "256x341" 
> EndSubSection
> 
> SubSection "Display"
> Depth 24
> Virtual 1920 1200
> Modes "1920x1200" "720x400" "640x480" "640x480" "800x600" "720x400"
> "720x400" "640x480" "640x480" "800x600" "256x341" 
> EndSubSection
> 
> EndSection
> 
> Section "DRI"
> Group 0
> Mode 0666
> EndSection
>