Hi Tapas,
I think IE8 is OK.
But as I mentioned there will be an issue with the changings for java script: sam_js2bsp_sender.js of BSP sam_sess_queue. Please, compare the coding with the attached file in following note 1309227. If there is a differece, correct it manually in the system.
Also, make sure the polling service under /DEFAULT_HOST/SAP/WEBCUIF/NOTIFY is active, you can refer to manual steps and attachment in following note too. Please also check BSP application sam_notifying view "sam_polling.htm", and make sure you are using the new service '/sap/webcuif/notify/polling/
1309227 - CRM IC: Problems with SAP WebDispatcher (CRM 5.2 onwards)
https://launchpad.support.sap.com/#/notes/1309227
Also, if above didn't help you. Then you can refer to following note to check what you have defined for polling frequency. You may try to increase the polling frequency of the polling mechanism for Broadcasting according to your business requirement.
1574747 - Polling mechanism slows down CRM WebUI performance
https://launchpad.support.sap.com/#/notes/1574747
Best Regards, Bruce