Ugh. I have the same exact issue right now. Even regular HD looks grainy with the X1 box. Did you ever get it resolved. I’m so angry I have a new tv where the graininess is so bad it doesn’t even look like HD let alone 4K.
How is your TV connected to your X1 box? Which box do you have?
Ryryjohn, I'd be happy to take a look at things on the back end to see if there are any related issues. Please send me a private message with your full name and phone number for help.
Its connected through brand new HDMI Cable. I've tried 3 other HDMI cables and get the same grainy picture.
I have the ARRIS XG1v4 box.
I had a Comcast Tech come out. He said the signal from comcast is fine, but agreed the picture quality was not good. He basically said the new X1 boxes just came out in Atlanta and they have gotten a few of these same types of calls. Basically, he said there was nothing he could do. He said ask for an older non X1 box.
You can imagine how frustrating it is when the tech says all the "Comcast checklist" items are good, but agreed my picture was not HD quality.
Ryryjohn, thanks for the update. Sorry to hear this outcome from the tech visit. Did you mention if this was happening to all of those boxes or just a few of them. We can try to do a like for like swap.