I was having frequent time-out issues, especially when trying to upload to third-party hosts. Finally, I may have found a tip that appears to have significantly improved FTP performance and reduced upload times. Simply disabling design notes has made a quantifiable difference. I don’t use Dreamweaver features that require the notes so disabling them wasn’t an issue.
Though the tip was for Adobe Dreamweaver CS4 and earlier it worked in the CS5 version that I’m using.
From an Adobe Knowledgebase Article:
Disable Upload Design Notes in Site Definition
Sometimes having the Upload Design Notes option checked in the site definition can cause problems. Uncheck this option and see if the problem persists: Site > Manage Sites, select your site, then click Edit > Advanced tab > Design Notes category > uncheck “Upload Design Notes for sharing”.