A few test shots to compare the high-ISO performance of the two cameras in terms of noise and detail. Click on each range to see a comparison.

Test parameters:
Lens: 24-70L on both cameras with focal length adjusted to roughly equal framing.
Manual mode to equalize exposure levels between the two cameras.
Converted in DPP with middle-range settings on all RAW parameters (saturation, contrast, etc.)
Lighting was incandescent with DPP WB set to "tungsten" for all shots.
f/11 used for all shots to eliminate DOF issues on primary subject.
All images are 100% crops, unsharpened and unprocessed except as noted above for conversion.