Let clarify this to avoid confusion; are you saying that PS5 will downclock as much as 12% and its custom continuous boost+smartshift feature isn't any different from a stock PC GPU's variable frequency like RX 480?
It is actually not different in terms of tech... the ability to down and up clock exists in all processors.
It is different in terms of implementation...
Radeon boost clock is based in power target while PS5 is based in workload.
The data, you can call logic, they use to down or up the clock is different.
RX 480 had issues... it should never go below base clock but it reached a high power draw making the clocks go below the base clock... RX 580 doesn’t suffer that issue anymore... some independent test showed that just using a lower vcore stabilized the clock so it could be something in AMD settings.
Now the 12% I have no ideia... I just used some random numbers to explain... PS5 drops clock below 2230Mhz how much depend of the workload but I have no ideia what these clocks are.
BTW GPUs doesn’t have Power Control unit for Smart Shift... it is only exists in APU and PS5 uses a customer Power Control unit due the logic being different from AMD.
Just being clear... the difference in PS5 is the logic customized in the Power Control that send the signal to GPU/CPU down/upclock.