diff --git a/spacy/serialize/huffman.pyx b/spacy/serialize/huffman.pyx
index 27b88f5ae..87a8cc41a 100644
--- a/spacy/serialize/huffman.pyx
+++ b/spacy/serialize/huffman.pyx
@@ -1,3 +1,4 @@
+# cython: profile=True
 cimport cython
 from libcpp.queue cimport priority_queue
 from libcpp.pair cimport pair
@@ -74,6 +75,8 @@ cdef class HuffmanCodec:
         node = self.root
         cdef int i = 0
         cdef int n = len(msg)
+        cdef int branch
+        cdef bint bit
         for bit in bits:
             branch = node.right if bit else node.left
             if branch >= 0:
diff --git a/spacy/serialize/packer.pyx b/spacy/serialize/packer.pyx
index 7ed4e85e9..f0e376410 100644
--- a/spacy/serialize/packer.pyx
+++ b/spacy/serialize/packer.pyx
@@ -106,17 +106,21 @@ cdef class Packer:
         return cls(vocab, util.read_encoding_freqs(data_dir))
 
     def pack(self, Doc doc):
-        orths = [t.orth for t in doc]
-        chars = doc.string.encode('utf8')
+        orths = doc.to_array([ORTH])
+        orths = orths[:, 0]
+        cdef bytes chars = doc.string.encode('utf8')
         # n_bits returns nan for oov words, i.e. can't encode message.
         # So, it's important to write the conditional like this.
         if self.orth_codec.n_bits(orths) < self.char_codec.n_bits(chars, overhead=1):
-            bits = self._orth_encode(doc)
+            bits = self._orth_encode(doc, orths)
         else:
-            bits = self._char_encode(doc)
-        array = doc.to_array(self.attrs)
-        for i, codec in enumerate(self._codecs):
-            codec.encode(array[:, i], bits)
+            bits = self._char_encode(doc, chars)
+        
+        cdef int i
+        if self.attrs:
+            array = doc.to_array(self.attrs)
+            for i, codec in enumerate(self._codecs):
+                codec.encode(array[:, i], bits)
         return bits
 
     def unpack(self, BitArray bits):
@@ -134,9 +138,8 @@ cdef class Packer:
         doc.from_array(self.attrs, array)
         return doc
 
-    def _orth_encode(self, Doc doc):
+    def _orth_encode(self, Doc doc, attr_t[:] orths):
         cdef BitArray bits = BitArray()
-        orths = [w.orth for w in doc]
         cdef int32_t length = len(doc)
         bits.extend(length, 32) 
         self.orth_codec.encode(orths, bits)
@@ -145,46 +148,47 @@ cdef class Packer:
         return bits
 
     def _orth_decode(self, BitArray bits, n):
-        orths = [0] * n
+        orths = numpy.ndarray(shape=(n,), dtype=numpy.int32)
         self.orth_codec.decode(bits, orths)
         orths_and_spaces = zip(orths, bits)
         cdef Doc doc = Doc(self.vocab, orths_and_spaces)
         return doc
 
-    def _char_encode(self, Doc doc):
+    def _char_encode(self, Doc doc, bytes utf8_str):
         cdef BitArray bits = BitArray()
-        cdef bytes utf8_str = doc.string.encode('utf8')
         cdef int32_t length = len(utf8_str)
         # Signal chars with negative length
         bits.extend(-length, 32)
         self.char_codec.encode(utf8_str, bits)
-        for token in doc:
-            for i in range(len(token)-1):
+        cdef int i, j
+        for i in range(doc.length):
+            for j in range(doc.data[i].lex.length-1):
                 bits.append(False)
             bits.append(True)
-            if token.whitespace_:
+            if doc.data[i].spacy:
                 bits.append(False)
         return bits
 
     def _char_decode(self, BitArray bits, n):
-        chars = [b''] * n
-        self.char_codec.decode(bits, chars)
-        cdef bytes utf8_str = b''.join(chars)
+        cdef bytearray utf8_str = bytearray(n)
+        self.char_codec.decode(bits, utf8_str)
 
         cdef unicode string = utf8_str.decode('utf8')
         cdef Doc tokens = Doc(self.vocab)
-        cdef int i
         cdef int start = 0
         cdef bint is_spacy
         cdef UniStr span
         cdef int length = len(string)
-        iter_bits = iter(bits)
-        for i in range(length):
-            is_end_token = iter_bits.next()
+        cdef int i = 0
+        cdef bint is_end_token
+        for is_end_token in bits:
             if is_end_token:
                 slice_unicode(&span, string, start, i+1)
                 lex = self.vocab.get(tokens.mem, &span)
                 is_spacy = (i+1) < length and string[i+1] == u' '
                 tokens.push_back(lex, is_spacy)
                 start = i + 1 + is_spacy
+            i += 1
+            if i >= n:
+                break
         return tokens