Recently I finished migration from Exchange 2010 SP3 to Exchange 2013 CU2 (now CU3). My configuration is: 2*CAS servers in WNLB-cluster and 2*Mailbox servers in DAG. 3 databases (30-150GB each) and small Public Folders Mailbox (about 2GB at all).
Now I have a problems with PF performance:
1) When I opening PF in Outlook 2013 and OWA - they work great, messages opens very fast.
2) When I opening PF in Outlook 2007 - they work a little bit slower, but also good (appears delay about 1 sec when changing message in PF)
3) When I opening PF in Outlook 2010 - messages opens extremly slow (Outlook hangs and not responding in this moments), it takes about 20-30 seconds for one message! And this is only for new messages, which came after migration: when I opening messages which are 2 weeks old (received by Exch 2010 before migration), they opens fine. But if i trying to open messages received today - Outlook hangs.
I'm using cache for main mailbox, but PF without cache. If I enabling cache for Public folders, Outlook 2010 completely hangs. Checked on many computers - everywhere the same picture with Outlook 2010. All latest patches for Exchange and MSOffice are installed.
I tried to move Public Folders mailbox to another database - nothing changed. No corrupted messages were detected on move.
It is not a performance issue too: all servers have 10-20% CPU use and about 50% free RAM.