- Extract your NVidia drivers with WinZip to a directory
- Open the NV4_DISP.INF file in notepad
- Scroll down until you see the listings of resolutions and refresh rates, example:
HKR,, NV4_Modes, %REG_SZ_APPEND%, "8 800 600 60 70 72 75 85 100 120 0"

- Find the listing that points to the card you have, then make a copy of the 800x600 resolution line directly below it and change that to say 856x480. Here's an example for TNT (NV4) owners, note that the NV4_Modes section will differ to say NV10, NV15, etc.
BEFORE:
HKR,, NV4_Modes, %REG_SZ_APPEND%, "8 800 600 60 70 72 75 85 100 120 0"
AFTER:
HKR,, NV4_Modes, %REG_SZ_APPEND%, "8 800 600 60 70 72 75 85 100 120 0"
HKR,, NV4_Modes, %REG_SZ_APPEND%, "8 856 480 60 70 72 75 85 100 120 0"

After you edit the .INF file, install the drivers. To simplify things for people who dont care how its done, I have modified the WinXP 23.11 NVidia drivers .INF file to work with all NVidia cards, Just grab this and save it in to your extracted drivers directory, overwriting the .INF file that comes with the package from NVidia. Install those drivers and you'll be good to go. DOWNLOAD AND INSTALL THESE AT YOUR OWN RISK. I've been doing this for quite a while so I dont think there is any real risk involved, but dont come crying to me if your machine blows up and your wife leaves you.

Now, in any Quake3 engine game, RTCW, MoH, Quake3 (heh) just launch the game with +set r_mode 11 or type r_mode 11 then vid_restart at the console. You may wish to play with r_displayrefresh and also adjust your monitor to have black bars at the top and bottom so things arent distorted. This is letterbox, so unless you've got a widescreen monitor you're gonna give up a little screen space just like watching widescreen movies on a regular TV.

Lastly, if you're a megahax0r you may wish to play with r_customheight and r_customwidth and do your own fruity resolutions that you feel like plugging in. I havent messed with that much but I assume it can be done.