Quote Originally Posted by TinCow View Post
If you've switched it on they'll keep spawning regardless of whether you're killing them or not. However, I strongly recommend you do not AFK with it activated for more than a minute or so. The mobs accumulate so quickly if you are not killing them that it will start to lag the entire server if you let it get out of hand.
I went AFK with the Arena spawner for about half an hour. I had no lag with that. But you're supercharged spawner seems like it will lag a lot.