We'll start with the usual proviso: your overclocking mileage may vary and discussions with various partners lead us to believe that frequency headroom fluctuates significantly from one sample to the next. Our chip seems to be a good one and had no qualms about running at 4.7GHz across all 10 cores. Heck, it needed only 1.25V to make it happen.
Could frequencies go higher with more voltage? Probably, but putting 1.3V through the Core i9-7900X veins resulted in temperature soaring beyond 100ºC and automatic throttling. We swapped out our favoured Noctua NH-D15S in favour of an EVGA CLC 280 liquid cooler but even that couldn't cope with the increase in voltage. The good news for users who have invested in a high-quality cooler for LGA2011v3 is that compatibility with LGA2066 has been retained with identical mounting-hole positions.
Still, a stable 4.7GHz across 10 cores at 1.25V is an impressive feat and we suspect enthusiasts are going to enjoy tinkering on X299. Revealing how power thirsty the chip can be, the Core i9 platform pulled just over 350 watts from the wall with the overclock in action. Good news for cooler manufacturers.