this seems pretty decent for ISO 25600:
This shot has so heavy noise reduction you could do the same with any high iso from a any dslr, if you are ok with a sharpness that looks like a lens you just made yourself from the bottom of a coke bottle...
especially in contrast to an iphone at ISO 3200:
Yipee Yay, the $2100 1,5kg 6d is better than a mobile phone - and there are people who say Canon is behind in sensor performance :->