答案是修改 \STEAM\SteamApps\你的帳號名稱\half-life 2\bin
裡面的dxsupport.cfg 檔
如果是5900XT的卡
尋找到這一段


"386"
{
"name" "NVidia GeForce FX 5900XT"
"VendorID" "0x10DE"
"MinDeviceID" "0x0332"
"MaxDeviceID" "0x0332"
"m_nDriverVersion_Build" "6177"
"DefaultRes" "1024"
"MaxDxLevel" "90"
"DxLevel" "81"
"NoUserClipPlanes" "1"
"ConVar.r_fastzreject" "1"
"ConVar.mat_forcemanagedtextureintohardware" "0"
}


改成如下

"386"
{
"name" "NVidia GeForce FX 5900XT "
"VendorID" "0x10DE"
"MinDeviceID" "0x0332"
"MaxDeviceID" "0x0332"
"m_nDriverVersion_Build" "6177"
"DefaultRes" "1024"
"ConVar.cl_detaildist" "1600"
"ConVar.cl_detailfade" "400"
"NoUserClipPlanes" "1"
"ConVar.r_fastzreject" "1"
"ConVar.mat_forcemanagedtextureintohardware" "0"
}


其他Geforce fx系列 依型號,去找到自己該改的那一段~
FPS確實掉很多,但是還不會影響遊戲進行~