Hello bamn
I just did what you need two days ago!
I'm going to tell you each step, but keep in mind that i'm using red hat 9 and some paths may be differ, so look for the correct one.
In the linux system there is 6 levels (runlevels) of functionality. They differ mainly in the servicess that are running. Let's get a little explain:
+The last and the first will never be used., they are for init and reboot purposses.
+The 5 is the level of multiuser and x windows works.
+The 3 is the same that the 5 but without x system.
+The 2 is the level of single user system.
So you need to change the runlevel to 3 to shut down x system and when your are finished return to level 5.
Execute as root this in a virtual shell (# stands for the prompt and a virtual shell is a virtual console that opens with CTRL+ALT+some function key from F1 to F5. I recommend F1)
#telinit 3
Yo will see the messages of stoping services and initing others.
If the prompt doesn't come back hit enter or CTRL+c .
Now i recommend to you to use the nvidia auto installable driver pack.
Get if from here:
http://www.nvidia.com/content/drivers/drivers.asp
Select your product and then the SO.
So make it executable (lets use nvidia-drivers.run as the name of the package):
#chmod +x nvidia-drivers.run
Then execute:
#./nvidia-drivers.run
This will install everything and guide you throuh some steps.
After that you need to make some changes in the config of the x server.
Go to the directory of the configuration, tipically /etc/X11
#cd /etc/x11
Make a backup of the actual file:
#cp XF86config XF86config.backup
Edit the file with vim
#vim XF86config
press i to enable modification mode and change the "nv" driver for the "nvidia" driver.
Put a "#" in the beggining of each line you want to comment.
Comment the lines that loads modules like "DRI" or "GLX".
to exit the editor press ESC and then the ":" and then put "w" and "q" and hit enter. (you can use any editor, you know).
now its time to return to the normal level:
#telinit 5
Hit CTRL+ALT+F7 or F8 to get to the graphic enviroment.
And now in a shell execute nvidia-config (i don't remember the exact name, push tab at the end to auto-complete),. You have to be able to configure your nvidia card.
I hope be in help, my desktop now goes at top speed