There are several factors that can slow Magento down. We look at the following:
The right balance of the above items will make your Magento instance very fast. We have solved this issue for small to complex sites.
Hosting also plays a big role. You do not necessarily need a “big” dedicated server but it definitely needs to be Magento optimized hosting. We will give you specific recommendations for server configuration. IronPlane is also a certified AWS partner with a highly custom Magento solution.
Sometimes it helps to have a fresh pair of eyes review your code.
A code review can be relatively straight forward or require in depth discovery. We can review the basics by phone to see what you need.