diff --git a/Library/Homebrew/os/mac/hardware.rb b/Library/Homebrew/os/mac/hardware.rb
index ace1368428..4cd8eb775d 100644
--- a/Library/Homebrew/os/mac/hardware.rb
+++ b/Library/Homebrew/os/mac/hardware.rb
@@ -68,6 +68,10 @@ module MacCPUs
     end
   end
 
+  def extmodel
+    @extmodel ||= `/usr/sbin/sysctl -n machdep.cpu.extmodel`.to_i
+  end
+
   def cores
     @cores ||= `/usr/sbin/sysctl -n hw.ncpu`.to_i
   end