Found this review from Overclockers and this is what they said during the conclusion of the review: AMD Ryzen 7 2700X and Ryzen 5 2600X CPU Review - Overclockers
Conclusion
I would like to mention that both CPUs behaved nearly identical when it came to voltage requirements. Both CPUs were stable at 4.0 GHz and 1.3V set in BIOS, 4.2 GHz with 1.4V and 4.3 GHz with 1.45V set in BIOS. Anyone familiar with the Ryzen platform will also know about the V-Droop associated with it. On both motherboards that is still present but easily addressed with some LLC (Load Line Calibration) tuning.
From the same link above:
Pushing the Limits
Now the moment you’ve all been waiting for, “so how fast will they go?” I have a few pictures to post here, I spent most of my limited time working with the Ryzen 7 2700X, but for this adventure, I switched over to my EKWB Predator 360 XLC closed loop cooler for improved cooling which took me up to 4.3 GHz and fairly stable at that. I was able to run the AIDA64 stability test for over an hour, because of time restraints that was all the stability testing I did, but it gives you an idea of what these CPUs are capable of. At 4.3 GHz, I was also at my voltage limit of 1.45 V but I’m certain with a bit more time that frequency would be completely stable for 24/7 usage. I’m also including a screenshot at 4.2 GHz that was done with the Wraith Prism cooler and the G.Skill SniperX 3400 MHz running at 3666 MHz. The last screenshot is all out tuning at 4.3 GHz on the MSI Motherboard, I have the FlareX 3200 MHz running at 3733 MHz with tight timings.
and:
Just one more screenshot, this one is really all out. If there are any that haven’t figured this out yet, I’m an extreme bencher at heart. I have a custom loop consisting of a Phobya 1260 SuperNova, a 750 GPH pump, and a Koolance 380A block modified to fit the AM4 socket. To top it off the liquid is chilled well below ambient, let’s just say in the snowflake range. This is what I use for testing before I go to LN2 in order to get an idea of how hardware will scale with colder temperatures. The hardware is the same with the same settings as the previous screenshot but I have upped the CPU speed to 4.55 GHz and bumped the voltage to 1.5 V for the CPU core. It needed that extra 0.05V to go from 4.5 GHz to 4.55 GHz, 4.6 wasn’t going to happen at that voltage.
I need to add a disclaimer here. What I have done is well out of the normal operating parameters of this hardware. If you try this at home you most likely will break something, so here it comes “Don’t try this at home” this will definitely void your warranty!