diff --git a/zone/CMakeLists.txt b/zone/CMakeLists.txt
index 1a8820a1c..b8897c1f3 100644
--- a/zone/CMakeLists.txt
+++ b/zone/CMakeLists.txt
@@ -276,7 +276,7 @@ set(lua_sources
 
 add_library(lua_zone STATIC ${lua_sources})
 if (MSVC)
-    set_target_properties(lua_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 8)
+    set_target_properties(lua_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 4)
 else()
     set_target_properties(lua_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 8)
 endif()
@@ -311,7 +311,7 @@ set(perl_sources
 
 add_library(perl_zone STATIC ${perl_sources})
 if (MSVC)
-    set_target_properties(perl_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 8)
+    set_target_properties(perl_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 4)
 else()
     set_target_properties(perl_zone PROPERTIES UNITY_BUILD ON UNITY_BUILD_BATCH_SIZE 8)
 endif()