Here is the deal: when my web server starts up, it creates a couple of lengthy (20M of elements) arrays with really small objects (like 1-2-3 ints). The accumulative size of any individual array is NOT larger than 2GB (the limitation of CLR, see the link below for some details). The w3wp.exe does grow in memory usage close to 2GB (never more than that). The code is compiled in Any CPU platform mode and run on Windows 7 x64 with 8GB of RAM.
What on earth makes it to throw OutOfMemoryException while creating my lists? Does it make any difference if I host the process thru IIS or VS? This appears not happening is PROD but I am experiencing this on my dev machine all the time. (Will try to restart now...)
This may be related but I don't seem to have objects that big: Very large collection in .Net causes out-of-memory exception
EDIT: It does make difference to run in IIS or VS - don't see that happening when the process is started in IIS. So could it be VS debugger limitation?
Based on your updated question, it's obvious that Visual Studio does not run in 64 bit mode. So your limitation is 2GB under Visual Studio.
This post probably contains some code helpful to prove this fact: How to detect Windows 64-bit platform with .NET?