diff --git a/libtransmission/fdlimit.c b/libtransmission/fdlimit.c
index ea226c53b..51ab6dc94 100644
--- a/libtransmission/fdlimit.c
+++ b/libtransmission/fdlimit.c
@@ -399,6 +399,24 @@ TrOpenFile( tr_session             * session,
     }
 #endif
 
+#if defined( SYS_DARWIN ) 
+    /**
+     * 1. Enable readahead for reasons described above w/POSIX_FADV_SEQUENTIAL.
+     *
+     * 2. Disable OS-level caching due to user reports of adverse effects of
+     *    excessive inactive memory.  However this is experimental because
+     *    previous attempts at this have *also* had adverse effects (see r8198)
+     *
+     * It's okay for this to fail silently, so don't let it affect errno
+     */
+    {
+        const int err = errno;
+        fcntl( file->fd, F_NOCACHE, 1 ); 
+        fcntl( file->fd, F_RDAHEAD, 1 ); 
+        errno = err;
+    }
+#endif
+
     return 0;
 }