You may want to go to the Windows performance monitor in the control panel to make sure your hard drive isn't being overloaded from running both a high traffic forum and high traffic mysql server. If you don't have a ssd, that may be the case here.
If you look at the link below, it looks as if your server hangs a longer than usual amount of time on every file request, both scripts and images. http://www.webpagetest.org/result/120919_6X_6C3/1/details/cached/
This may be because the overloaded hdd issue stated above. At the above link, you will notice there is a lot of green on the first request, that means the server doesn't recognise the request until after the seconds it shows.
Not by any means am I saying this is the problem for certain. Just make sure your not overloading your hard drive. If you are not, then post back and I'll troubleshoot some more.