nVidia drivers 180.60 are the latest drivers that enable you to manually tweak PowerMizer state and frequency clocks. Unfortunately these drivers are not compatible with the default kernel of Ubuntu linux Karmic 9.10. In order to install them you first need to patch these drivers as detailed step by step here.Download the drivers (first command/link is always for x86 32bit OS, second one is for x86_64 64bit OS) 
wget http://us.download.nvidia.com/XFree86/Linux-x86/180.60/NVIDIA-Linux-x86-180.60-pkg1.run
wget http://us.download.nvidia.com/XFree86/Linux-x86_64/180.60/NVIDIA-Linux-x86_64-180.60-pkg2.run
unpack it 
sh NVIDIA-Linux-x86-180.60-pkg1.run -x
sh NVIDIA-Linux-x86_64-180.60-pkg2.run -x
put create an empty text file with this content 
--- /usr/src/nv/nv-linux.h    2009-07-30 11:31:54.069234343 +0200
+++ /usr/src/nv/nv-linux.h    2009-07-30 11:38:44.857538204 +0200
@@ -721,7 +721,7 @@
 #define nv_up(lock)                     up(&lock)

 #if defined(CONFIG_PREEMPT_RT)
-#define NV_INIT_MUTEX(mutex) init_MUTEX(mutex)
+#define NV_INIT_MUTEX(mutex) semaphore_init(mutex)
 #else
 #if !defined(__SEMAPHORE_INITIALIZER) && defined(__COMPAT_SEMAPHORE_INITIALIZER)
 #define __SEMAPHORE_INITIALIZER __COMPAT_SEMAPHORE_INITIALIZER
save it with the name patch and place it into the extracted .run package folder (it's called NVIDIA-Linux-...) then from a terminal after having entered the folder with 
 cd NVIDIA-Linux-[PRESS TAB]
patch -p1 <patch
run nvidia-installer. To do this save all the documents you are working on and close all the open programs. Then switch console with 
CTRL+ALT+1
login, get root access 
sudo -s
terminate gdm or kdm 
service stop gdm
service stop kdm
go to the folder where you had patched the files previously (it's called NVIDIA-Linux-...) and run the installer 
./nvidia-installer
follow the procedure and reboot. If you get a libgl.so.1 error do a symlink 
ln -s /usr/lib /usr/lib32