steamapps\common\Left 4 Dead 2\left4dead2\cfg\video.txt

"VideoConfig"
{
"setting.cpu_level" "2"
"setting.gpu_level" "0"
"setting.mat_antialias" "1"
"setting.mat_aaquality" "0"
"setting.mat_forceaniso" "1"
"setting.mat_vsync" "1"
"setting.mat_triplebuffered" "0"
"setting.mat_grain_scale_override" "0.000000"
"setting.mat_monitorgamma" "2.196800"
"setting.gpu_mem_level" "2"
"setting.mem_level" "2"
"setting.mat_queue_mode" "-1"
"setting.defaultres" "1920"
"setting.defaultresheight" "1080"
"setting.aspectratiomode" "1"
"setting.fullscreen" "0"
"setting.nowindowborder" "1"
"setting.mat_tonemapping_occlusion_use_stencil" "1"
}