Different decode chip. The chip in the one in the 622 does mpeg2/mpeg4 and was suppose to do VC1. The VC1 decoding didn't work. Because of this change the 722 receivers more Video on Demand (dowloaded material) in HD then the 622. The 622 usually only having the one 1080P movie a month, while pretty much all of the other is in HD on the 722, but SD on the 622.
Note the new 722K is of course a log different than the 722. And the 922 is suppose to be coming soon.
622 /silver/ 30 hrs of hd/ 1 ota tuner 722 /black/55 hrs of hd/1 ota tuner 722k/black/55 hrs of hd/2 ota tuner with ota tuner module sold seperately. 922s/black/? hrs of hd /2 ota tuner with ota tuner module sold seperately.
I don't know for sure how many hours of recording on the 922s but it will have 1 tb of hard drive and it will allow 500gb for DISH use and 500gb for the customer.
The only difference I have noticed is a 5- point difference between ota tuner 1 & ota tuner 2 on the same ota channel. It was a bigger problem when the 722k was first released and it caused drop outs and pixelation on some channels while recording. But since the latest software update the strength on both ota tuners has become more in line with the single ota tuners in the 722 & 622 dvrs. It is more consistent and I haven't noticed any more drop outs or pixelation ,unless the channel itself is breaking up at the station.
Strength- Tuner 1/2-network-digital channel
74/70 - ABC - 12.1 main channel 74/70 - NBC - 12.2 sub channel 86/84 - CBS- 6.1 main channel 86/84 -Cw - 6.2 sub channel 78/73 -Fox - 4.1 main channel
*** Oh, but one piece of advice. If you do get the 722k , first let the receiver download the latest software first ,before you add the ota module. It is recommended and if not followed you will see problems. I did it the wrong way and had to pull the ota module back out and reinstall it to get it to work correctly.