Current caching is good. I can't test during the day, but during lower peak usage, the wiki is loading fast for me. The larger culprit is being driven by a spike in in-bound connections that starts just after 9AM server time. This directly impacts server load. Increasing the number of processes to handle more connections will also directly impact server load, potentially more negatively than the current state. You also have to take Pingdom with a grain of salt to a certain extent. It is connecting as if it is a first time user, which means there is no benefit of client side caching of all of the resources such as CSS, JS, images, and initial page view. There are a lot more resources being loaded for the Wiki compared to the Forum. A test via Pingdom in the past 10 minutes reported a little over 10 second load time, but a refresh in my browser was under 3 seconds. There are some things I can look at implementing to help reduce the stress further, but will take some time to setup and test.