Yes, 921 is like a computer with a hard drive, its constantly writing data to its hard drive as its received (usually quiets down in about 3 - 5 days) and you can't fully power off a dual tuner because its also made to work a second TV in another room that needs the box running as well. Let me guess, you let the Tech install the box in the master bed room so you can drown out the ticking of that anoying clock you have hanging on the wall with sweet melodies of High Def power rocking through your entertainment center? }
While the 921 has a dual satellite tuner, it is not a dual room receiver. The 942 can be used as a dual room receiver. I've had my 921 for 1 1/2 years. It's just as loud today as the day I first plugged it in.
I have a 921 and a 6000, I have news for you the 921 is silent compared to the loud 6000. Has a fan that you can hear 3 rooms away and is very annoying to say the least.
Some of us were waiting with bated breath for an HD-DVR and got our 921s before E* even thought about the 942 - which IMO only really came about because of the dismal failure of the 921.