Fe-Fi-Fo-Fum, I smell the blood of a troll... or something that rhymes with "fum" that means the same thing.
You call out a camera for producing "poor quality images" by posting a single shot utterly lacking in EXIF data, and devoid of all other information pertaining to lenses and shooting circumstances, so I'm sorry, but I have to call Shenanigans.
I purchased this same camera 2 weeks ago. I spent the prior 19 months shooting with little other than a D600 and D800. My first post about the purchase dealt specifically with just how sharp the images from this camera are, and the quality of the photo I am able to get from a DX sensor. So pardon me if I question your motives, but if it's not that then it has an awful lot to do with your technique, or a lack of understanding on how to use the camera in your hands. You're shooting indoors with no flash. Yes, the room is white. But if you're pushing ISO levels to the high side then I suspect that you're going to see "grainy" images, particularly against solid colors.
I do see that you've posted elsewhere about being a "Beginner Real Estate Photographer", and you're having issues with your flash, so if this is of a genuine nature then I apologize for the accusation and would recommend that you learn how to use your gear before you try and make some money doing real estate photos. There are certainly people here who can help, but you've got to offer way more information than you've been offering with the two complaints you've posted already.