I have encountered an issue with Excel RTD. I have reproduced this
problem with a number of third party RTD servers (e.g. Bloomberg) and
also in a "test" RTD server taken from this article:

http://support.microsoft.com/kb/285339/

The issue is that when running Excel in Manual Calculation mode,
inserting or deleting a row or column anywhere in a spreadsheet
containing RTD calls causes a Disconnect Data call for each RTD
function, followed by a ServerTerminate call. The spreadsheet is now
disconnected from the live data. Pressing F9 causes the RTD server to
reconnect.

This behaviour does not occur when Excel is run in Automatic
Calculation mode.

THe problem is that when you have a sheet with thousands of RTD calls,
taking minutes to start up, inserting or deleting a column or row
ANYWHERE in the sheet causes a delay of several minutes until all the
data is received.

Has anyone seen anything like this?