Overheating is out of the question. The Internet connection might be the problem as I'm back in my home town for a few weeks and I have a weird connection here.

I tried using both dedicated ports for X11 and X13 on TMB, but then I tried to switch to Scrypt as well since Razercoin became more profitable some days ago. What I did was to include the 3330 port together with the 4010 and 4011 ports and that's when I started to notice the miner idles after some time. Then you released the TMB Switcher software and wanted to try it, but I still got that random idling (miner stops and waits for work from pool). So I tried 4010/4011 + 3330 and 5550/4440 + 3330 and it makes no difference when it comes to this idling. I haven't been able to figure out what triggers it yet, as I managed to catch it one time after 20 minutes and another time after 1 hour, yet another time after 7 hours. The Internet connection might be responsible for the 20 mins idling, however I doubt that those 1h+ idlings are triggered by the connection, as I haven't notice any connection dropout longer than 30 mins.