Hello,

When my ASP.NET web site encounted a specific situation (described below), w3wp.exe indefinitely (for at least several hours) consumed from 97% to 99% of the CPU time on the server.
This problem is not described on the Microsoft web sites. There are articles referring to w3wp.exe consuming too many resources (CPU or memory), but those articles say the problem was fixed in a prior version of w3wp.exe. And they refer to different situations.

Situation:
When a data table (TableAdapter) (created using the visual designer in Visual Studio 2005) with a field having a System.Byte data type retrieves data with a value too large for the field, it causes the problem with w3wp.exe.
When the field is changed to System.Decimal, and the data table again retrieves data, the problem is resolved (w3wp.exe CPU usage goes down to 0).
The data table's data source is an Access database. The Access field was originally a Byte data type, and was changed to Integer. The data table was not updated.

Environment:
I am using Visual Studio 2005 on a Windows XP sp2 computer, working on an ASP.NET (Visual Basic) project located on a Windows Server 2003 SBS sp2, with IIS 6.0. The Win XP computer is joined to the Domain on the SBS computer, and connected via LAN. The 2 computers are sitting next to each other, and I was able to monitor processes on SBS while working on the XP. Both computers have all current updates.

Visual Studio 2005 Standard, Version 8.0.50727.762 (SP.050727-7600)
ASP.NET version: 2.0.50727 (on both computers)
W3wp.exe (on the server):
 Version: 6.0.3790.3959 (srv03_sp2_rtm.070216-1710)
 Location: C:\Windows\system32\inetsrv\
 Date: 2/17/2007
 Size: 7168 bytes