My 881U is overheating after a couple of hours of use. And I mean, hot, like it will burn you if you hold it more than a few seconds. When it gets this hot, it then starts disconnecting. It isn't near any heat source on the laptop. I've tried it on a couple of laptops and it does the same thing.
I would have suspected the radio working at max wattage due to weak signal but if another card does not behave this way in the same location, that all but completely kills my theory. Not important to this thread at all but I'm curious if you are using two usb ports by chance with one of those adapters that only use the second usb plug for power, not data seeing as how you can only get .5amps or 500ma from a single usb port, in this case it is amazing how much heat a half an amp can produce if you only use a single usb port. 5v and 500ma would make 2.5w of total power dissipation possible, well, a 2.5w lightbulb can burn you so why not? e*i=p.
I had thought about that as well, and moved it to a couple different usb ports to test, but it got hot no matter which one I used.
I talked to AT&T tech support yesterday. They are going to replace it for me. The guy I talked to said that he has not seen this problem before. So, maybe I just got a defective one. I'll check back when I get the new one to see if it exhibits the same problem.