I've been observing this for quite awhile, and I'm not sure what I should make of it. I have an Exchange 2003 Server running Windows 2003. I've noticed that at least IMAP service gets slowed to a crawl periodically, and at the same time I see on the perfmon that my Avg Disk write time, Avg Disk Que length, Avg Disk bytes write, and Avg Disk Bytes transfer all max out. I'm assuming that would be an indication of poor disk speed. I have a 3ware RAID 5 controller 9550SX-4LP. The firmware is out of date. Could that be the problem? I don't see any errors reported in the controllers logs. What else should I look for? It's a tough problem to troubleshoot because anything I can think of to try means taking the server down, and it's our only email server. How would an expert handle this? I also seem to be the only person who notices, other than the other admin who also uses IMAP. Everyone else has an exchange account, and I don't think it's been affecting them. Any suggestions would be helpful.