It doesn't take much of a voltage increase at all to send power usage skyrocketing.
That said the part you're missing is binning. The 3800x is definitely the worst binned chiplets, as evidenced by the 3900x and 3950x having the same TDP.
TDP is just a number these days. You're not getting 4 more cores for free, you're getting a cap put on your all-core power consumption at a lower clock rate. More cores, lower all-core boost clocks (the advertised clocks are single-core boost).
Even then, both AMD and Intel CPUs will pull significantly above their rated TDP when boosting. It's not quite a base-clock measurement (eg 9900K is more like 4.3-4.4 when 95W-limited) but it's definitely not a boost power measurement either.
Again, pretty much just a marketing number these days.
> You're not getting 4 more cores for free, you're getting a cap put on your all-core power consumption at a lower clock rate.
There's a mere 100mhz difference in base clock. Which is what TDP is based off of. No where close to enough of a reduction to fully explain +50% cores at the same TDP
> Again, pretty much just a marketing number these days.
Not really no. You just need to understand it represents all core base frequency thermal design target, and not maximum power draw.
It's still based in reality, though. It's not some random made up number.
And binning is an extremely real thing with very significant impact. Not sure why you seem to be trying to outright dismiss it.
That said the part you're missing is binning. The 3800x is definitely the worst binned chiplets, as evidenced by the 3900x and 3950x having the same TDP.