From the numbers I can check at DxO the D300s handles noise a bit better than the D300 but better is in the context of those days. Compared to ISO performance of most cams now, they perform not that well.
The overall ISO score of them is:
D300: 679
D300s: 787
D7100: 1256
Those numbers (higher is better) are just an indication, to know how well it performs through the range, you'll have to check the whole measurements.
The overall ISO score of them is:
D300: 679
D300s: 787
D7100: 1256
Those numbers (higher is better) are just an indication, to know how well it performs through the range, you'll have to check the whole measurements.