You could try to remove google desktop add-in in outlook 2007 if you feel the outlook is abnormally slow.

I believe the problem could be credited to the background action by google desktop search.

Update at 20100423, one topic proves my guess.

https://mediawiki.middlebury.edu/wiki/LIS/Google_Desktop_and_Outlook_Issues 

Outlook is unresponsive or slow and gives a warning bubble

Message from Outlook: "Microsoft Outlook is Requesting data from the server." or "Trying to retrieve data..."

This can happen if Google Desktop is installed. Here's a brief explanation and some helpful tips: Unfortunately, with large volume of mail, Google Desktop spends more time indexing and re-indexing, and to do this it briefly takes over the connection to the exchange server. this is why Outlook is giving the message.

There is no known solution for this. What helps:

disable other Outlook add-ins (I disabled the iTunes add-in)

install the latest version of Google Desktop

if you need to use outlook for a time and not be bothered by the message, run outlook in safe mode (See Running Outlook in Safe Mode. Note that new messages are not indexed while outlook is in safe mode.

decreasing the number of messages / folder (not necessarily deleting them, but splitting them up in different folders, such that there is less than 1000/folder)