Isso é possível graças a um recurso chamado “ Intel Turbo Boost ”:
Intel® Turbo Boost Technology 2.0 automatically allows processor cores to run faster than the rated operating frequency if they’re operating below power, current, and temperature specification limits.
Intel Turbo Boost Technology 2.0 is activated when the Operating System (OS) requests a frequency higher than the rated frequency of the processor. Whether the processor enters into and the amount of time the processor spends in the Intel Turbo Boost Technology 2.0 state depends on the workload and operating environment.
Maximum turbo frequency indicates the highest possible frequency achievable when conditions allow the processor to enter turbo mode. Intel Turbo Boost Technology frequency varies depending on workload, hardware, software and overall system configuration.
Due to varying power characteristics, some parts with Intel Turbo Boost Technology 2.0 may not achieve maximum turbo frequencies when running heavy workloads and using multiple cores concurrently.
(ênfase minha)
Então sim, é possível e o 3.1 GHz indicado é a velocidade máxima do Turbo Boost.