Please look at the Cluster article for more information about Distributed Orders Cluster.
Setting
To use the improved load balancing in distributed orders you have to configure the ./config/scheduler.xml:
...
<params>
<param name="scheduler.variable_name_prefix" value="SCHEDULER_PARAM_"/>
<param name="scheduler.order.keep_order_content_on_reschedule" value="false"/>
<span style="color:red;"><[http://www.sos-berlin.com/doc/en/scheduler.doc/xml/param.xml param] name="scheduler.order.distributed.balanced" value="true"/></span>
</params>
...