For our temperature testing, we measure the peak GPU core temperature under load, as well as the GPU temperature with the card idling on the desktop. A reading under load comes from running the 3DMark Fire Strike Ultra stress test 20 times. An idle reading comes after leaving the system on the Windows desktop for 30 minutes.
As for GPU temperatures, starting with BIOS 1 here the GPU peaked at 70C, a reduction of 5C versus the Founders Edition but 2C hotter than the Gaming X Trio. Either way, it's a great result and nothing at all to worry about.
BIOS 2 did run slightly hotter, with higher idle temperatures as well due to the fan-stop mode which is only available on that secondary BIOS, but under load it is still 3C cooler than Founders.
These thermal images were taken when using BIOS 1, and there is nothing to be concerned about – hot spots of 64 and 68C are great results.