SQL Server 2012: Notifications table and events table get queued up

Our current Production server has SQl Server 2008 installed. We have about 8k report subscriptions running on this server every morning at 2.00 am without any issues. We bought more efficient new servers and SAN to replace our existing production server. We set up everything on this new servers installed SQL Server 2012 restored a backup of our production data and started testing the box. We noticed that after couple of successful subscription runs the box becomes unresponsive while processing report subscriptions. We are able to access the database via Management Studio but not able to access the box itself until we reboot the box. We checked the report server log files and notice warnings - "Schedules, events, and subscriptions processing may be delayed because processing queue reached the maximum item count = 48. Items currently being processed: 48." We tried setting 'WorkingSetMaximum' to 4000000 and 'WorkingSetMinimum' to 2400000 in 'RSReportServer.config' as suggested in: http://social.msdn.microsoft.com/Forums/sqlserver/en-US/471da874-c09e-4daa-87ea-e7d4563b99f2/report-sereport-server-windows-servicerver-windows-service-event-142-flooding-event-logs Still no change we are still seeing the same issue. We turned on Verbose logging and we see messages indicating that the server is stressed for memory. Our monitors indicate that not even half of the available memory is being used. Did anyone run into this issue? Any information regarding this issue will be very helpful.