It also makes me lag when I am using it to form a group. The solution to the problem I've found without having to turn the addon off is as follows.
#1.) Open OQ.
#2.) Go to the "Setup" tab on the bottom.
#3.) Fourth from the bottom on the right, click the check mark off for "Auto join oqgeneral channel."
Once that's clicked, the game immedietely goes back up in FPS.
Cheers,
M.
Note: If this is clicked off, you will not be able to see any of the raids, bg's, arena's etc until it's clicked back on. If you're ready to start looking again, repeat the steps above, and click it back on. The lag will resume, but you can see the groups and be able to form your own groups (if it's clicked off, your wait list will not fill), or join others.