diff --git a/borg/archiver.py b/borg/archiver.py
index ffb71f20b..d5eae5431 100644
--- a/borg/archiver.py
+++ b/borg/archiver.py
@@ -1212,7 +1212,8 @@ def build_parser(self, args=None, prog=None):
             Both archives need to be in the same repository, and a repository location may only
             be specified for ARCHIVE1.
 
-            For archives created with Borg 1.1 or newer only chunks IDs
+            For archives created with Borg 1.1 or newer diff automatically detects whether
+            the archives are created with the same chunker params. If so, only chunk IDs
             are compared, which is very fast.
 
             For archives prior to Borg 1.1 chunk contents are compared by default.
diff --git a/docs/usage/diff.rst.inc b/docs/usage/diff.rst.inc
index 47a8676fa..ba07b8203 100644
--- a/docs/usage/diff.rst.inc
+++ b/docs/usage/diff.rst.inc
@@ -48,7 +48,8 @@ This command finds differences in files (contents, user, group, mode) between ar
 Both archives need to be in the same repository, and a repository location may only
 be specified for ARCHIVE1.
 
-For archives created with Borg 1.1 or newer only chunks IDs
+For archives created with Borg 1.1 or newer diff automatically detects whether
+the archives are created with the same chunker params. If so, only chunk IDs
 are compared, which is very fast.
 
 For archives prior to Borg 1.1 chunk contents are compared by default.