diff --git a/HISTORY.rst b/HISTORY.rst
index b2a6be6..9f0cedd 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -3,6 +3,10 @@
 Release History
 ===============
 
+0.0.52 (2020-11-29)
++++++++++++++++++++
+* Don't invalidate cache when opening files with mode rb, speed up small reads 2x.
+
 0.0.51 (2020-10-15)
 +++++++++++++++++++
 * Add more logging for zero byte reads to investigate root cause.
diff --git a/azure/datalake/store/core.py b/azure/datalake/store/core.py
index 9427ae1..f40e5d0 100644
--- a/azure/datalake/store/core.py
+++ b/azure/datalake/store/core.py
@@ -993,7 +993,8 @@ def __init__(self, azure, path, mode='rb', blocksize=2 ** 25,
         # always invalidate the cache when checking for existence of a file
         # that may be created or written to (for the first time).
         try:
-            file_data = self.azure.info(path, invalidate_cache=True, expected_error_code=404)
+            invalidate = mode != 'rb'
+            file_data = self.azure.info(path, invalidate_cache=invalidate, expected_error_code=404)
             exists = True
         except FileNotFoundError:
             exists = False