Grain is a part of HD life..like it or not...more so for 1080p that are lower bitrate...sometimes, 720p version look better for some movies because it is not so demanding and easier to get a better pictures with a lower bitrate rather than 1080p version.
There are many reasons to grain.
1)The movie itself.
Older movies tend to grain more due to the limitations of Video camera they were using, especially for those higher ISO shot like moving, panning, dark areas etc. But some movies that are not so demanding have very clear pictures...
Some movies even were shot with grain in them to make those effect like 300, BSG....but I'm not sure of Black Hawk Down.
The best movies without grain are like The Dark Knight, Discovery Channels Documentary etc that are shot with the best video equipment there is.
2)The transfering or converting.
Movies converted to Bluray, then MKV or whatever will occur graining in them depending on how it was encoded. If you check TF2 MKV, there are so far 3 type of bitrate available..about 9000Kbps, 13000kbps, 16000kbps...of course 16000kbps will have the least graining. But it depends also, even for TF2 some shot are grainy especially when they close up the face etc.
Some old movies have 'Restored', 'Remastered' etc version done before/during the transfering..example Fifth Element, Wizard of Oz.
3)Hardware.
Cable interferes, bad connection, also effect graining, try to do some adjustment to the routing of the cable and replug back the connectors to make sure fully fitted.
Below is the media info, btw the screenshot is done via PC print screen. That means for 720p with high bit rates is better than 1080p with low bit rates? If for 1080p, what is the recommended minimum bit rate is required to achieve a decent quality?
Alamak ... if like that had wasted a lot of bandwidth to download those 1080p movies but with low quality.....