Hi all, i finally got some improvement in performance by adding this in my web.config
<behavior name="SilverlightWCFLargeDataApplication.Web.SilverlightWCFServiceBehavior">
<serviceMetadata httpGetEnabled="true"/>
<serviceDebug includeExceptionDetailInFaults="false"/>
<dataContractSerializer maxItemsInObjectGraph="2147483647"/>
</behavior>
</serviceBehaviors>
</behaviors>
hope it helps me to achive my goal.
Can any one please suggest any other better way.
Thanx