diff --git a/src/backup/chunker.rs b/src/backup/chunker.rs
index f1014460..7e19d9e7 100644
--- a/src/backup/chunker.rs
+++ b/src/backup/chunker.rs
@@ -1,4 +1,4 @@
-const CA_CHUNKER_WINDOW_SIZE: usize = 48;
+const CA_CHUNKER_WINDOW_SIZE: usize = 64;
 
 /// Slinding window chunker (Buzhash)
 ///
@@ -161,14 +161,16 @@ impl Chunker {
             self.start();
         }
 
-        let mut idx = self.chunk_size % CA_CHUNKER_WINDOW_SIZE;
+        //let mut idx = self.chunk_size % CA_CHUNKER_WINDOW_SIZE;
+        let mut idx = self.chunk_size & 0x3f;
 
         while pos < data_len {
             // roll window
             let enter = data[pos];
             let leave = self.window[idx];
             self.h = self.h.rotate_left(1) ^
-                BUZHASH_TABLE[leave as usize].rotate_left(CA_CHUNKER_WINDOW_SIZE as u32) ^
+                //BUZHASH_TABLE[leave as usize].rotate_left(CA_CHUNKER_WINDOW_SIZE as u32) ^
+                BUZHASH_TABLE[leave as usize] ^
                 BUZHASH_TABLE[enter as usize];
 
             self.chunk_size += 1;
@@ -183,7 +185,8 @@ impl Chunker {
                 return pos;
             }
 
-            idx = self.chunk_size % CA_CHUNKER_WINDOW_SIZE;
+            //idx = self.chunk_size % CA_CHUNKER_WINDOW_SIZE;
+            idx = self.chunk_size & 0x3f;
             //idx += 1; if idx >= CA_CHUNKER_WINDOW_SIZE { idx = 0 };
         }
 
@@ -191,7 +194,7 @@ impl Chunker {
     }
 
     // fast implementation avoiding modulo
-    #[inline(always)]
+   // #[inline(always)]
     fn shall_break(&self) -> bool {
 
         if self.chunk_size >= self.chunk_size_max { return true; }