For our temperature testing, we measure the peak GPU core temperature under load. A reading under load comes from running Cyberpunk 2077 for 30 minutes.
As for thermal performance, considering the size of the Gaming OC and the vapour chamber, it's not really a surprise to see excellent results here. We don't yet know how this will compare to other AIB models, but with the OC BIOS keeping GPU temperatures below 60C, it's hard to imagine much of an improvement will be had.