The major difference between DM900 and the DM820 HD or DM7080 HD is the obvious addition of 4K support - or at least that's the main selling point of this new Dreambox satellite receiver. First impressions are very good - the look of the box is quite decent, far from the disasterous design of the first 4K receiver - the Solo 4K (reviewed here). The flashing and booting time is excellent, as it was the case with DM820 HD, and the community support continues trying make the most out of this, otherwise quite dull, receiver. This is also the first ARM Dreambox receiver, which means you'll need to pay extra attention when installing plugins or cross compiling for this receiver.
I've tried couple of unofficial images but in the end I found OpenATV and pbnigma to be the best ones once again. The other ones seemed unstable and amateurish. Flashing a new image and being completely booted up for the first time takes 70 seconds so there's no reason not to try all the images out there and find your favorite. General rule of thumb would be that if the box doesn't crash on you during the first 10 minutes of usage, stick to that image because not many will manage not to crash. Despite OpenATV and pbnigma being the images of my choice, there's still lot to be improved. For example, 2160p only supports 50Hz video mode, which makes no sense since you will want to play 60Hz material too. For this reason I'm running the receiver at 1080p only, which is OK considering there's not really any 4K content. But this must be fixed!
Another major issue with many unofficial images is that they seem to bring the receiver's speed down. The menu navigation doesn't feel as snappy as it does with the original image. But the official image is not perfect either. For example, in 4K, the skin looks like shit. It's really interesting to see a 4K receiver with no 4K skin. This is yet another reason to simply run the box at 1080p. It's even more annoying to see the old GUI with no graphical improvements in 10 years, or even more. Oh wait, they added animations! Really? That's it? Anyway, it's not any better with other, unofficial, images. The user interface is good, but it's gotten a bit boring over the years. I would like to see some exciting new stuff, I'm sure the hardware has enough horsepower to do that and what better opportunity than releasing a 4K receiver would there be?
There's something else I must point out because I think it's a major letdown. The media player. It sucks. I've tried playing 4K content using the Media player plugin and also Plex plugin. First thing I noticed is that Plex is still incredibly slow and that pissed me off. Why is this plugin so fast even on Vu+ Zero but slow on Dreambox, even the latest DM900? And then, when I actually got to playing a 4K movie, it looked so bad! The colors were all washed out, certainlyl not 10 bit 4K stuff! I don't really know what's wrong - something so essential not working at all. On the other hand, 4K satellite channels look good. It's just the media player (including Plex) not being able to handle 4K files and that's a shame. I think this is something that should be fixable in the future but that's not making it less irritating!
The dual tuner inside is nothing exceptional. Not only does it not report correct SNR but it's having a hard time locking marginal signals. But to be fair, not even DM820 HD or Vu+ Zero could lock such signal and show error-free video, although a cheap DVBSky S960 USB tuner could show clean video. What's a little bothering is the overrated SNR reporting. I don't really believe 7.5 dB could produce perfect image when we're talking 8PSK and 3/4 FEC - there's something definitely not right with this, as we all know, these modulation parameters won't end up showing a clean video until 7.9 dB SNR and there's no magic to get around this fact.
Other than this, the DM900 UHD works as you would expect. Fast, stable and quiet. Especially the quiet part is really pleasing as there's no fan inside the box, yet it keeps calm during operation. That's a nice plus. Another good thing about the DM900 UHD is PowerVu emulation support, which works without stream relay, but there's still the old problem when zapping between DES and CSA encrypted channels requires box restart and which in makes stream relay a better option anyway. However, this isn't really Dreambox's fault.
Overall, I like DM900 UHD but it would be hard to justify an upgrade just because of 4K. I needed a new satellite receiver and this one came at a very reasonable price and it does what it's supposed to do. It wasn't supposed to be a media player and I wasn't expecting anything else than what DM820HD couldn't already do. I'm just quite disappointed because this is a very powerful hardware, yet the software innovation is absolutely zero. Great to see Dream Multimedia keeping the pace and adding 4K, but wouldn't it be nice to finally come up with something new? It seems they're relying too much on the community to provide all skins and plugins for the Dreamboxes but I actually don't think this is working. We haven't seen any real software imrovements in years and most Enigma2 images produced by the community don't really know how to keep up with the hardware improvements.