I have a 2 core server (2 x 2.66 GHZ INTEL Xeon) w/ 8 GM Ram and 50 GB 15,000 RPM HDD space. This is a VM running w/ VM ware and is running Microsoft Server 2008R2. We have had some performance issues recently. We have up to 350 users w/ multiple devices/sessions per user and sometimes 800 sessions at once. We are pushing out data (about 100KB per file) on an average of every 3 minutes. It is a reporting application that updates the data for everyone so they all have the data in real-ish time.
We are hosting a .net application written in C# though IIS server 7.5. We are running 2 worker processes. We do no have memory utilization above 5 GB (out of 8) and disk I/O seems fine.
The processor queue length has been generally above 50 and has averaged as high as 120. Microsoft says it should be between 2 and 6.
I am happy to answer any questions you may have, and this is my first time on here so be nice if I didn't explain something correctly!
I am guessing that I need more CPU cores, please let me know your thoughts.