diff --git a/read-cache.c b/read-cache.c
index 29144cf879..a5b2779b95 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -2447,7 +2447,7 @@ int repo_index_has_changes(struct repository *repo,
 	}
 }
 
-#define WRITE_BUFFER_SIZE 8192
+#define WRITE_BUFFER_SIZE (128 * 1024)
 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
 static unsigned long write_buffer_len;