The Ryzen 5 2500X and Ryzen 3 2300X were spoiled a few months ago and were known to have the frequency multiplier unlocked for overclocking. On the other hand, the Ryzen 7 2700E and Ryzen 5 2600E are totally new additions designed for silent desktops and mini PCs, thus having lower TDPs and no overclocking support.
https://www.notebookcheck.net/AMD-intros-Ryzen-2700E-2600E-2500X-and-2300X-CPUs.329586.0.html