ATI 2600HD in 24" iMac - Horrible Performance

[sototallycarl]

I am running Ubuntu 8.10 on a 24" 2.8Ghz C2D iMac, 4gb ram, 256Mb ATI 2600HD, etc... And have noticed terrible performance since day one (even back on 8.04, ubuntu, kubuntu).

I have tried running without Compiz and the performance is no better. glxgears averages at about 1000fps. Compiz about 100fps - 120fps.

My xorg.conf is bellow:

Section "ServerLayout"
	Identifier     "aticonfig Layout"
	Screen      0  "Default Screen" 0 0
EndSection

Section "Files"
EndSection

Section "Module"
	Load  "glx"
EndSection

Section "Monitor"
	Identifier   "Configured Monitor"
EndSection

Section "Device"
	Identifier  "Configured Video Device"
	Driver      "fglrx"
	Option	    "XAANoOffscreenPixmaps" "on"
	Option	    "TexturedVideo" "on"
	Option	    "VideoOverlay" "off"
	Option	    "OpenGLOverlay" "off"
	Option	    "Textured2D" "on"
	Option	    "UseFastTLS" "1"
	Option	    "TexturedXrender" "off"
	Option	    "BackingStore" "on"
	BusID       "PCI:1:0:0"
EndSection

Section "Screen"
	Identifier "Default Screen"
	Device     "Configured Video Device"
	Monitor    "Configured Monitor"
	DefaultDepth     24
EndSection

Section "DRI"
	Group        "Video"
	Mode         0666
EndSection

Section "Extensions"
	Option	    "RENDER" "Enable"
	Option	    "DAMAGE" "Enable"
	Option	    "Composite" "Enable"
EndSection

Any help is greatly appreciate. Even if I can boost performance to a normal level, that would be awesome.

Carl

[rbmorse]

What does

glxinfo | grep direct

return about the status of direct rendering?

[bridgman]

NOt sure if it will help but you probably don't need the XAANoOffscreenPixmaps option any more.

What are you running when you see horrible performance ? Glxgears doesn't count

[sototallycarl]

What does

glxinfo | grep direct

return about the status of direct rendering?

direct rendering: Yes

I am running nothing really. I am checking from a fresh reboot, so the usual stuff on a typical Ubuntu system at login. I disabled compiz, cairo-dock, gnome-do and conky for good measure. None of these effected performance greatly.