It was written in submission... about -135-140 °C CB (measured on POT)... -125-130 °C benchable... on AIR it was average piece - 4,8 GHz rock stable, 5 GHz SuperPi 32M with 1,55 V! - so very bad chip on air...
Try to adjust VCCIN to 2,5 V, Vcore to 1,7-1,9 V and Ring V to 1,5 and it will be fine i think. Im my opinion - average batch, but I get most from it! Especially wPrime runs – 1024M on 5,9 GHz :-), 6,1 GHz SuperPi 1M, 6300 MHz validation (cause XPOWER dont have LN2 mod).