Quake 4: enable SLI in linux

Quake 4 also runs faster in SLI mode in Linux. However, it needs to configured properly to increase performance. Here is my Quake starup script with SMP enableled.

#!/bin/sh
# Needed to make symlinks/shortcuts work.
# the binaries must run with correct working directory
cd "/usr/local/games/quake4"
export __GL_DOOM3=1
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:."
exec ./quake4smp.x86 "$@"
export __GL_DOOM3=1

important is to add export __GL_DOOM3=1 to improve SLI performance