diff --git a/lib/memcached/memcached.rb b/lib/memcached/memcached.rb
index 8e7c005..6981506 100644
--- a/lib/memcached/memcached.rb
+++ b/lib/memcached/memcached.rb
@@ -308,7 +308,7 @@ Please note that when <tt>:no_block => true</tt>, update methods do not raise on
   # Also accepts a <tt>marshal</tt> value, which defaults to <tt>true</tt>. Set <tt>marshal</tt> to <tt>false</tt> if you want the <tt>value</tt> to be set directly.
   #
   def set(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
-    value = marshal ? Marshal.dump(value) : value.to_s
+    value = marshal ? Marshal.dump(value) : value
     begin
       check_return_code(
         Lib.memcached_set(@struct, key, value, ttl, flags),
@@ -325,7 +325,7 @@ Please note that when <tt>:no_block => true</tt>, update methods do not raise on
 
   # Add a key/value pair. Raises <b>Memcached::NotStored</b> if the key already exists on the server. The parameters are the same as <tt>set</tt>.
   def add(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
-    value = marshal ? Marshal.dump(value) : value.to_s
+    value = marshal ? Marshal.dump(value) : value
     begin
       check_return_code(
         Lib.memcached_add(@struct, key, value, ttl, flags),
@@ -374,7 +374,7 @@ Please note that when <tt>:no_block => true</tt>, update methods do not raise on
 
   # Replace a key/value pair. Raises <b>Memcached::NotFound</b> if the key does not exist on the server. The parameters are the same as <tt>set</tt>.
   def replace(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
-    value = marshal ? Marshal.dump(value) : value.to_s
+    value = marshal ? Marshal.dump(value) : value
     begin
       check_return_code(
          Lib.memcached_replace(@struct, key, value, ttl, flags),
@@ -504,14 +504,14 @@ Please note that when <tt>:no_block => true</tt>, update methods do not raise on
       check_return_code(ret, keys)
 
       hash = {}
-      keys.each do
-        value, key, flags, ret = Lib.memcached_fetch_rvalue(@struct)
-        break if ret == Lib::MEMCACHED_END
-        if ret != Lib::MEMCACHED_NOTFOUND
-          check_return_code(ret, key)
-          # Assign the value
+      value, key, flags, ret = Lib.memcached_fetch_rvalue(@struct)
+      while ret != 21 do # Lib::MEMCACHED_END
+        if ret == 0 # Lib::MEMCACHED_SUCCESS
           hash[key] = (marshal ? Marshal.load(value) : value)
+        elsif ret != 16 # Lib::MEMCACHED_NOTFOUND
+          check_return_code(ret, key)
         end
+        value, key, flags, ret = Lib.memcached_fetch_rvalue(@struct)
       end
       hash
     else
@@ -592,10 +592,10 @@ Please note that when <tt>:no_block => true</tt>, update methods do not raise on
   # Checks the return code from Rlibmemcached against the exception list. Raises the corresponding exception if the return code is not Memcached::Success or Memcached::ActionQueued. Accepts an integer return code and an optional key, for exception messages.
   def check_return_code(ret, key = nil) #:doc:
     if ret == 0 # Memcached::Success
-    elsif ret == Lib::MEMCACHED_BUFFERED # Memcached::ActionQueued
-    elsif ret == Lib::MEMCACHED_NOTFOUND and @not_found
+    elsif ret == 32 # Lib::MEMCACHED_BUFFERED # Memcached::ActionQueued
+    elsif ret == 16 # Lib::MEMCACHED_NOTFOUND and @not_found
       raise @not_found
-    elsif ret == Lib::MEMCACHED_NOTSTORED and @not_stored
+    elsif ret == 14 # Lib::MEMCACHED_NOTSTORED and @not_stored
       raise @not_stored
     else
       message = "Key #{inspect_keys(key, (detect_failure if ret == Lib::MEMCACHED_SERVER_MARKED_DEAD)).inspect}"
diff --git a/test/profile/benchmark.rb b/test/profile/benchmark.rb
index 184d4c8..51ee4d0 100644
--- a/test/profile/benchmark.rb
+++ b/test/profile/benchmark.rb
@@ -120,8 +120,12 @@ class Bench
   end
 
   def benchmark_clients(test_name, populate_keys = true)
+    return if ENV["TEST"] and !test_name.include?(ENV["TEST"])
+
     @clients.keys.sort.each do |client_name|
+      next if ENV["CLIENT"] and !client_name.include?(ENV["CLIENT"])
       next if client_name == "stash" and test_name == "set-large" # Don't let stash break the world
+
       client = @clients[client_name]
       begin
         if populate_keys
diff --git a/test/unit/memcached_test.rb b/test/unit/memcached_test.rb
index 5aa8f88..f080fe2 100644
--- a/test/unit/memcached_test.rb
+++ b/test/unit/memcached_test.rb
@@ -177,9 +177,8 @@ class MemcachedTest < Test::Unit::TestCase
   end
 
   def test_initialize_with_backtraces
-    cache = Memcached.new @servers,
-      :show_backtraces => true
-    cache.delete key rescue
+    cache = Memcached.new @servers, :show_backtraces => true
+    cache.delete key rescue nil
     begin
       cache.get key
     rescue Memcached::NotFound => e
@@ -404,9 +403,21 @@ class MemcachedTest < Test::Unit::TestCase
     assert_equal @marshalled_value, result
   end
 
+  def test_set_unmarshalled_and_get_unmarshalled
+    @cache.set key, @marshalled_value, 0, false
+    result = @cache.get key, false
+    assert_equal @marshalled_value, result
+  end
+
+  def test_set_unmarshalled_error
+    assert_raises(TypeError) do
+      @cache.set key, @value, 0, false
+    end
+  end
+
   def test_get_multi_unmarshalled
-    @cache.set "#{key}_1", 1, 0, false
-    @cache.set "#{key}_2", 2, 0, false
+    @cache.set "#{key}_1", "1", 0, false
+    @cache.set "#{key}_2", "2", 0, false
     assert_equal(
       {"#{key}_1" => "1", "#{key}_2" => "2"},
       @cache.get(["#{key}_1", "#{key}_2"], false)
@@ -415,7 +426,7 @@ class MemcachedTest < Test::Unit::TestCase
 
   def test_get_multi_mixed_marshalling
     @cache.set "#{key}_1", 1
-    @cache.set "#{key}_2", 2, 0, false
+    @cache.set "#{key}_2", "2", 0, false
     assert_nothing_raised do
       @cache.get(["#{key}_1", "#{key}_2"], false)
     end
@@ -566,12 +577,12 @@ class MemcachedTest < Test::Unit::TestCase
   # Increment and decrement
 
   def test_increment
-    @cache.set key, 10, 0, false
+    @cache.set key, "10", 0, false
     assert_equal 11, @cache.increment(key)
   end
 
   def test_increment_offset
-    @cache.set key, 10, 0, false
+    @cache.set key, "10", 0, false
     assert_equal 15, @cache.increment(key, 5)
   end
 
@@ -583,12 +594,12 @@ class MemcachedTest < Test::Unit::TestCase
   end
 
   def test_decrement
-    @cache.set key, 10, 0, false
+    @cache.set key, "10", 0, false
     assert_equal 9, @cache.decrement(key)
   end
 
   def test_decrement_offset
-    @cache.set key, 10, 0, false
+    @cache.set key, "10", 0, false
     assert_equal 5, @cache.decrement(key, 5)
   end