I have something new to add to this thread. We just got Dish Network installed yesterday afternoon. We got a 722k installed in the master bedroom. I noticed last night while we were watching TV the guide really slowed down, exactly as you are all describing it. Having just switched from DirecTV I was used to slow guides so I did not pay much attention to it. However, this is where the real problem started. A couple of hours after the guide started responding slowly the fan on the unit kicked on, full blast. It wouldn't quiet down, even when I turned off the unit. I couldn't sleep with that thing going full blast so I pushed the reset button on the receiver and the fan quieted down immediately. After the reboot, the guide went back to being fast, and the fan quiet again.
I'm very concerned that this happened on the first day we got the receiver. Is anyone else getting the slow guide symptom AND the fan kicking on full blast? For those of you who will surely want to ask... The receiver sits on top of the counter with nothing else around it that would cause poor ventilation or cause it to overheat. The room temperature is 65 - 68 degrees.