I have an ASP.NET 2.0 website running on IIS 7.5, Windows 2008 R2. The site gets pretty heavy traffic. All throughout the day, about every 66 seconds the Worker Process stops accepting or responding to requests for about 5 seconds, then starts accepting them again. When this happens, w3wp.exe CPU spikes up (mostly kernel mode usage) and all disk/network I/O ceases during that time. After the 5 second pause, there is a burst of activity as the Worker Process catches up on the queued up requests. I have researched this as far as I know how and am looking for some help. I have inserted a screencap of the process explorer performance graph. You can see the red (kernel mode) CPU spikes from w3wp and that I/O ceases during those spikes and then bursts with activity again. I initially thought this may be due to ADO connection pooling running out of connections (there is an access database behind this) but when I realized it is happening on a very regular 66 second interval i don't think this is the case. This cycle happens 24 hours a day, even when the application is hardly being used. Thanks in advance for any help!
