diff --git a/lib/fileutils.rb b/lib/fileutils.rb
index 0209adc..7d37e78 100644
--- a/lib/fileutils.rb
+++ b/lib/fileutils.rb
@@ -823,6 +823,8 @@ module FileUtils
   #
   def compare_stream(a, b)
     bsize = fu_stream_blksize(a, b)
+    a.advise(:sequential)
+    b.advise(:sequential)
     sa = ""
     sb = ""
     begin