diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/macaddr.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/macaddr.rb
index d0380ea750..13e77c6ab3 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/macaddr.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/macaddr.rb
@@ -9,10 +9,15 @@ module ActiveRecord
             :macaddr
           end
 
-          private
-            def cast_value(value)
-              value.to_s.downcase
-            end
+          def changed?(old_value, new_value, _new_value_before_type_cast)
+            old_value.class != new_value.class ||
+              new_value && old_value.casecmp(new_value) != 0
+          end
+
+          def changed_in_place?(raw_old_value, new_value)
+            raw_old_value.class != new_value.class ||
+              new_value && raw_old_value.casecmp(new_value) != 0
+          end
         end
       end
     end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
index 4548d75e7e..78f05429d8 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/uuid.rb
@@ -7,15 +7,25 @@ module ActiveRecord
         class Uuid < Type::Value # :nodoc:
           ACCEPTABLE_UUID = %r{\A(\{)?([a-fA-F0-9]{4}-?){8}(?(1)\}|)\z}
 
-          alias_method :serialize, :deserialize
+          alias :serialize :deserialize
 
           def type
             :uuid
           end
 
+          def changed?(old_value, new_value, _new_value_before_type_cast)
+            old_value.class != new_value.class ||
+              new_value && old_value.casecmp(new_value) != 0
+          end
+
+          def changed_in_place?(raw_old_value, new_value)
+            raw_old_value.class != new_value.class ||
+              new_value && raw_old_value.casecmp(new_value) != 0
+          end
+
           private
             def cast_value(value)
-              casted = value.to_s.downcase
+              casted = value.to_s
               casted if casted.match?(ACCEPTABLE_UUID)
             end
         end