diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 79d6d213939..808276c4639 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -4606,18 +4606,19 @@ class BaseModel(object):
         order_by = self._generate_order_by(order, query)
         from_clause, where_clause, where_clause_params = query.get_sql()
 
-        limit_str = limit and ' limit %d' % limit or ''
-        offset_str = offset and ' offset %d' % offset or ''
         where_str = where_clause and (" WHERE %s" % where_clause) or ''
-        query_str = 'SELECT "%s".id FROM ' % self._table + from_clause + where_str + order_by + limit_str + offset_str
 
         if count:
-            # /!\ the main query must be executed as a subquery, otherwise
-            # offset and limit apply to the result of count()!
-            cr.execute('SELECT count(*) FROM (%s) AS count' % query_str, where_clause_params)
+            # Ignore order, limit and offset when just counting, they don't make sense and could
+            # hurt performance
+            query_str = 'SELECT count(1) FROM ' + from_clause + where_str
+            cr.execute(query_str, where_clause_params)
             res = cr.fetchone()
             return res[0]
 
+        limit_str = limit and ' limit %d' % limit or ''
+        offset_str = offset and ' offset %d' % offset or ''
+        query_str = 'SELECT "%s".id FROM ' % self._table + from_clause + where_str + order_by + limit_str + offset_str
         cr.execute(query_str, where_clause_params)
         res = cr.fetchall()