From what I can tell, there are four caching events that go on once you access the site - the first time per session. Then, subsequent times afterward accessing the site will cause the pages to load slow. This is a website compatibility issue.
Solution #1: Try the above methods (posts 1 and 2).
If that fails, go to 2.
Solution #2: Run Firefox in Safe Mode. Usually Start Menu > All Programs > Mozilla Firefox > Mozilla Firefox (Safe Mode). Then, try to access the site. If you can access the site, go to step 3. If you cannot access the site, go to step 4.
Solution #3: Disable different add-ons, and restart Firefox, and attempt to connect to GeekPolice. The problem add-on will be noticeable. When you find the problem add-on, disable it. If you cannot find the problem add-on, go to step 4.
Solution #4: Change Privacy Settings like so:
If this does not help, go to step 5.
Solution #5: Disable the following add-ons if they exist. Tools > Add-ons.
-FasterFox
-DownloadHelper
-Fastest Fox
-NoScript (unless you allow all scripts on GeekPolice)
-Cooliris
-FlashGot
These add-ons seem to have a weird effect on web forums (not just this one, but several others). Especially DownloadHelper and FlashGot.
If this does not help, go to step 6.
Solution #6: Delete your current user profile, and then create a new one for Firefox: http://support.mozilla.com/en-US/kb/Managing+profiles
Solution #7: Reinstall Firefox. Go to Add or Remove programs (Or Programs in Vista/7) located in the Control Panel. Uninstall Firefox, BUT keep settings. Then, download and install a fresh version from http://www.getfirefox.com
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I hope this has helped.