I have an exchange 2010 environment configure pretty well as a hub and spoke. My Exchange server is configured at the hub with 32 Gb of ram, dual quad core processors and also does double duty as a BES Express server. I have about 100 users, and 40 of those use Blackberries.
All of my subnets are working properly with Global Catalogs in each and no replication issues. DNS resolves well and quickly.
Last week, I started having users in one of my sites complaining that there email isn't arriving fast enough and that they need to close outlook 2007 and reopen it to get emails. By their definition Outlook connects to exchange on opening, they'll receive any waiting emails and then it stops. Occasionally it will be like someone opens the floodgates and allows all the email to go thru. They can speed this up by closing and reopening the outlook client.
The users are all using Cached mode.
While shadowing one of these users I could not replicate the issue. ( I sent them an email and watched it arrive within a second or two.)
The site in question contains a Global Catalog and is connected to the site containing the Exchange server via 5 Mb intercity Vlan.
I am at wits end with this as I can find no errors, cannot replicate the issue while shadowing them . The network is far from saturated, there is nothing to indicate the client is disconnected, but the users insist it is an issue.
Any thoughts on how I can "speed up" their situation.
If I am not being specific, please let me know and I can add more detail.