.NET "System.OutOfMemoryException"

Im .NET gibt es limitierungen zum adressieren von Memory. Hier eine Aussage vom Microsoft.
The recommended approach for tuning is to measure the total memory consumed by the ASP.NET worker process by measuring the Process\Private Bytes (aspnet_wp) performance counter along with paging activity in System Monitor. If the counter indicates that the memory consumption is nearing the default limit set for the process, it might indicate inefficient cleanup in your application. If you have ensured that the memory is efficiently cleaned but you still need to increase the limit, you should do so only if you have sufficient physical memory.
This limit is important to adjust when your server has 4 GB or more of RAM. The 60 percent default memory limit means that the worker process is allocated 2.4 GB of RAM, which is larger than the default virtual address space for a process (2 GB). This disparity increases the likelihood of causing an OutOfMemoryException.
To avoid this situation on an IIS 5 Web server, you should set the limit to the smaller of 800 MB or 60 percent of physical RAM for .NET Framework 1.0.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag/html/scalenetchapt17.asp

Der Artikel bezieht auf .NET 1.0 aber die Physikalischen Grenzen sind die selben.
http://support.microsoft.com/kb/820108/en-us