In camera noise reduction setting 5D3

Please comment on IQ when using the in-camera noise reduction settings on the 5D3

Would there be a preference to set it to a lower setting or off for say for ISO < 400

Then moderate for ISO 600-2000

Then higher for ISO > 2000

Or just keep it off and do noise reduction in post processing.

That said is the higher quality IQ at higher ISOs on the 5D in-camera software dependent?

Thank you