ISO comparison between the Sony A7rII and the A7, the A7rII in silent mode (I did shoot in regular mode but couldn’t see a difference on this particular subject), I wish I had a better subject matter and apologize for the unscientific quickie, slightly overcast, changing light which adds to exposure variations.
Screen grabs at 100% at ISO 5000 and 25600.

PLEASE NOTE: THE A7RII FILES ARE DISPLAYED AT NATIVE RESOLUTION AND DOWNSIZED TO 24MP.
Attention wedding photogrphers: it appears silent mode only works in single shot mode, unlike on the A7s where it is possible to fire away at 6fps. Bummer.

shot above: A7rII, ISO 5000, 100% at 42.2mp

shot above: A7rII, ISO 5000, 100% at 24mp

shot above: A7, ISO 5000, 100% at 24mp

shot above: A7rII, ISO 25600, 100% at 42.2mp

shot above: A7rII, ISO 25600, 100% at 24mp

shot above: A7, ISO 25600, 100% at 24mp

I hope this gives you an idea how good this sensor is, downsized to 24mp it appears slightly cleaner, hell, no, a lot cleaner at 25600, then the fantastic A7 sensor. My guess, it will score at 99 on DXO
The screen grabs are off a Mac-book Pro Retina, which means they are interpolated and appear soft when viewed at 100%, download, resize to your liking for better comparison.

If you find this post inspiring, please consider helping me maintaining this blog by purchasing your gear through my product links to Adorama and B&H and Ebay. It will cost you nothing and allows me to keep adding! Or consider making a direct donation using PayPal, thank you!