diff --git a/README.md b/README.md
index d1f6e5ec..12e06f4d 100644
--- a/README.md
+++ b/README.md
@@ -135,6 +135,9 @@ set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
 Then point CMake at your toolchain file:
 `cmake -DCMAKE_TOOLCHAIN_FILE=/path/to/Toolchain.cmake -DDHEWM3LIBS=/path/to/dhewm3-libs/i686-w64-mingw32 /path/to/repository/neo`
 
+If you want to build for x86_64 aka AMD64 aka x64, replace all instances of `i686`
+in the toolchain file with `x86_64`.
+
 ## Back End Rendering of Stencil Shadows
 
 The Doom 3 GPL source code release **did** not include functionality enabling rendering