OK, there's definitely speckling in the
Really dark portions of your photo.
I can't see the EXIF , but if its ISO100 as stated, its definitely not "normal".
I deliberately shot at ISO100 -2 E/V in a dimly lit room just now, with both my K-7 and trusty K100D. The photos look awful, but they are clean - even the darkest portions are quite free from noise.
If its a consistent problem, I would say there is very likely a problem with your K-7 unit
Sorry, just a curious side question....why would you deliberately underexpose a dimly lit room by -2 E/V ? A very bright outdoor scene I can understand, but a dark-ish room ?