Database Opimisations to speed up site

Background: We are a UK-based market research and consulting agency. We have an existing, working website for our community of 150,000 young people before, during and after their time at university. Our website at [login to view URL] is built in WordPress, with many customisations of our own, and runs on our own, collocated Windows Web Server 2008. The main database for WordPress and associated functionality sits on the web server itself. The website links to an external providers SQL database where our community data is stored by a software provider. We use custom functions for read and write access to said database to facilitate community members logging into our website, checking incentives etc. The Task: We are happy with how the site looks and functions, but current load times are unacceptably slow. This is largely due to calls to the internal SQL databases, which account for about 15-16 seconds(!) of the overall 18 seconds load time. The task is to reduce the overall page load time to under 4 seconds (as measured by [login to view URL]‘s speed test) by heavily optimising database calls and database caching. WordPress caching can also be explored, but so far it has been a struggle to find a WP caching option that works with our user login process. We are however open to any sensible combined approach of DB caching and WP caching. Please quote the word “gazelle” in your response to be considered. The project will only be considered to be successfully completed if the page load times drop below 4 seconds, without affecting any of the site’s user-facing functionality. There will be no partial success/partial payment arrangement. Payment will be in full upon the successful completion of the project within the agreed time frame. Required Skills: A solid understanding of generic web technologies and specifically WordPress in an IIS (not Apache!) environment. Well-versed in IIS and Windows Server admin interfaces. Expert-level skills in MySQL and MS SQL, especially in the fields of speed optimisation and caching. Framework: The deployed technology (IIS, WordPress, PHP and extensions/customisations) needs to be unchanged. All SQL queries need to be sanitised. Timeline: Please supply your proposal by close of business on Tuesday, July 16th. We will pick a suitable freelancer by close of business on Wednesday, July 17th. This project is fairly urgent; the work needs to be completed by close of business on Wednesday, July 24th. This includes testing, amends and sign-off by YouthSight.