"As you already has understood – the new Nikon D5 camera is in my opinion not only a small improvement, but has set new standards especially regarding the AF-system and High ISO performance which will be hard to beat for other camera models. For me it looks like Nikon has found back to the “Nikon DNA” and again has a camera that is on top of the line. I’m really looking forward to get my final version of this camera (not Beta) and use it on my upcoming photo expeditions."
Ole's article includes several amazing photos taken with the D5 (more D5 photos from Ole can be found here, here, here and here). There are also some high ISO samples:
NIKON D5, 600/4.0, 1/500 SEC AT F/6.3 AND ISO 102 400
NIKON D5, 24/1.4, 1/30 SEC AT F/1.4 AND ISO 51 200
NIKON D5, 600/4.0 + 2.0X EXTENDER, 1/320 SEC AT F/10 AND ISO 25 600