Stock: ± 15-19 °C on all coresThat thing is damn big mate
What are your temps like? I might build a 100% silent pc
(SSD's, no opticals, passive cooling, etc.) :3
@ 4.2 GHz: just a tad higher: ± 23-27 °C (didn't run prime yet, but it's only being used as a bedroom PC atm

I put some back-up fans in the case though, which will be enabled by a fan controller at 45°C (I know it's a low temp, but they didn't turn on yet
