That's in the scenario when there's a light workload. I'm talking about a scenario when there's enough workload to peg all of the cores for a significant amount of time.
And again, I don't believe Ryzen has independent clocking for each core, so once you hit more that two cores, that best core is going to clock down.
Ryzen clocking is independent for each core and you can see that in the core boosting behavior in HWInfo64.
3rd gen will only boost one core at a time to maximum rated clocks but will shift the boost to another core in the same core complex as the scheduler moves the thread to that core so as far as the processing load cares it's still getting the higher performing boost. The scheduler is aware of the core architecture and knows to move threads to cores with shared resources so there's limited to no latency loss, and further knows the CPU's core ranking order. That's what CPPC is all about.
I've an early silicon 3700X that only hits max rated clocks on 6 cores. When I run a light processing load with say 2-4 threads it bounces them around those 6 cores round-robin style. I'm sure none are ever maxxed at the same time, but then no utility can show that since the algorithm makes decisions 100 times a second. Thats way faster than any utility polling period (500mS what I've set HWinfo to).
You can't control each cores clocks for overclocking though...but you can control a die or CCX if I'm not mistaken. I don't do that so not too familiar with it how it works...or how it's different with 4th gen.
But as far as OP's titular question:
https://www.gamersnexus.net/guides/2835-amd-ryzen-r7-1700-smt-off-overclock-benchmarks
TL/DR: Even though these are 4 year old systems and older gaming titles it's still relevant as it shows one clear principle: it can depend on the game but it's mostly better with SMT on.