DSLR lighting problems? - 1

I have a Nikon D7000 and when I would take pictures indoor where its darker, I would need to raise the ISO to 6400 and the shutter to 1/40 of a second to make balance the exposure but i don't want to use the flash because I want the most natural lighting possible. But when the setting are like this, the quality of the picture will be extremely bad. I use to have a Nikon D5200 and when I was indoor I could put the ISO at 320 and shutter at 1/100 a second and it would be perfect lighting. Is there something wrong with my D7000 or am I doing something wrong?

You mentioned the shutter and ISO what aperture are you using though? You may be using a small Aperture on the D7000 and a larger one on the 5200.