Hi, I Have the same problem:
Im use two video drivers: Intel e AMD Radeon series, for case of AMD radeon series show 511 degrees.
i'm use the last version of Speccy (Nov-2014)
the driever is up to date: Video_Driver_954YR_WN_10.18.10.3496_A01
The notebook is new (2 days) and i'm use windows 8.1 single edition 64 bits (yes, i'm update all security patches of windows).
Intel core i7