Canon aps-c bodies since the 7D are quite capable of good results at ISO 6400, and above. The evidence is all over POTN, and I imagine every other photo forum. I used a 60D for a while. I had to learn the camera, and my PP software (LR), but once I knew what I was doing, 6400 on the 60D was no mean trick. The 80D is better at 12800 as the 60D was at 6400, and I'm still learning that camera.
At 6400, there isn't a bunch of difference between the 80D and the 6D. My 6D starts to pull ahead of my 80D at 12800. At 25,600 the 6D is noticeably less noisy, and easier to clean up. At 25,600 I'm happy to get anything, on any body.
Sorry but no way they are equal at 6400,I have both the 6d and 7dmkii and there's no comparison at 6400. I stand firm on that one.The 7dmkii is ok up to 3200 after that it's your standards that are conpromised
I would say bring out the popcorn for this one but I did that once before and was chastised for being snarky so I guess I can't do that any more. Someone might be 'offended'.
And we sure wouldn't want that now.......
By the way, I agree with Bassat, there are many examples of good high ISO stuff from crops on here.