Hey,
Temperatures is a complex topic, sure, silicon lottery does play a good bit by requiring less voltage on a good binning, but so does the type of PC case, room temperature, humidity, fan placement, type of fan, gpu and so on.
In your case, since I believe you changed a little of these variants, could very well be the "lottery".
In the meanwhile, you can curve optimize it and even undervolt to get more for your bang.
Good luck!
The Englishman