This is a specialty area of mine. Performance tuning.
In projects like this my first order of business is to take metrics of all resources involved over a time period which we can work out (to determine peak usage times (if any). I can measure available versus used bandwidth (number of connections etc etc), available versus used CPU cycles, as well as taking a close look at the architecture to determine if there are any bottlenecks at any points in the tiers (web server, application server, database server, if applicable).
Once resource utilization is determined, which is an absolute first step in the process, we can move forward with ideas on how to fine tune the site.
Projects like this take someone who is well versed in all aspects of the architecture (hardware AND software). I have worked as a Unix Systems Engineer/Systems Architect for the past 20 years and thoroughly enjoy my work as well as projects like this.
Please review my past projects and profile and ask questions should you require any further information before awarding this project.
There are may talented engineers/hackers/SE's here on Freelancer and I hope that I may be one with whom you'll work with.
Thank you,
Ronald L. Johnson
925.255.5308
San Francisco Bay Area