Måske ville denne patch hjælpe på dit problem,her er lidt om hvad den gør
Microsoft Windows Vista Ultimate 64 Bit SP1
GRAPHICS:
* Interior Lights for ATI 1900 series cards:
o All light sources appear for users with 1900 series ATI cards. (ie. Pool Mini Game)
o ALT-TAB fixed
* Graphics Settings:
o Added menu option " OFF " for Reflection quality
o Added menu option " OFF " for Shadow quality
PERFORMANCE:
* Physics optimizations to improve situations with heavy physics calculations (ie. 32 player races)
* Graphical Performance Optimizations
MULTIPLAYER:
* NAT Type detection
o Detect if user has a " strict " NAT and displays message for user
* Voice chat is received even if your microphone is turned off
CONTROLS:
* Keyboard / Mouse
o Remapping restrictions removed
o Allow Enter, Backspace, and Arrow keys to be remapped by user
o Allow multiple mouse buttons to be mapped
* Enable/Disable DirectInput in Menu
o Users can now activate/deactivate Direct Input devices from "Controls" menu.
o If commandline "-usedirectinput" is active, it will override pause menu setting.
* Use 2 direct input devices simultaneously (ie. Wheel and Gamepad)
o Users can now use 2 different controllers at once, including 1 XInput and 1 Direct Input device.
* Added more Direct Input / XInput device support
o Saitek P380/P480/P580/P990
o Saitek PS1000/PS2700/P3200/P3600
o Gravis Eliminator Shock gamepad
SECURITY:
* Detect modified files and prevent users from entering multiplayer if found
o Game will prompt with a message after blocking user with modified data files from entering multiplayer
o Should prevent multiplayer access from cell phone and GFWL join in progress
VIDEO EDITOR:
* Scroll Bar improved response
o Tweaked to respond better to keyboard inputs
* Sped up load times for users with many clips
TITLE UPDATE 2 FIXES:
* Return of Hot Dog Stands and other props
o Missing hot dog vendors, fences, gates, pylons should be present throughout the world.
* Scrolling signboards
o Activate missing scrolling signboard text (ie. highway signs, Star Junction, Clock Tower Sign)
* ALT-TAB pauses game during cutscenes
o Cutscenes should now pause and resume correctly after an ALT-TAB task switch. Audio remains in sync.
GENERAL ADDITIONS / FIXES:
* Mismatched MODO/Perseus Clothing
o Fixed a bug when Niko mixes clothing from Perseus and Modo
* 360 Controller Texture
o Controller image should be visible in Controller Configuration screen
http://dlh.net/cgi-bin/dlp.cgi?lang=eng&sys=pc&file=gtaiv_patch_1030.zip&ref=ps