an ASP.NET performance bottleneck mystery

Question

A classic ASP.NET app - AppSrv + MS SQL DB. Both servers are heavy-lifters 8 cores, 20 GB of RAM. When load testing, the throughput goes somewhere to 400 VirtualUsers (according

Answer 1

When no CPUs are hosed and pages tend to become unresponsive, my first hunch is database locking. One thread can hold up the rest when not releasing a lock on a table, which results in non responsive pages while idling your db server.

Can you use a sql monitoring tool to verify proper usege on the database machine and see if all users get their data properly?

One other thing; what info can you give on memory use?