Again private companies may have quality control criteria that cannot be independently verified by third parties. TPU testing values have nothing to do with internal AMD spec decisions.
That's not how reality works. No, third parties don't have access to AMD's specific QC criteria or their engineering systems for determining TDPs and the like, but their TDP equation is public, as are the power draw limits of the chips and the platform, which are published openly as well as in much more detail to specialty press and partner companies.
What TPU does is test the real-world power draw - but up until the most recent round of testing they've only tested full-system power draw for CPUs, which is a severe methodological flaw, as it introduces far too much variance to produce reliable CPU power draw numbers. Depending on the application used to stress the system, full-system power draw can increase noticeably with a faster CPU at the exact same CPU-only power due to the faster CPU loading the RAM, PCIe, storage, or other subsystems more heavily. That TPU hasn't been using a clamp meter on the 12VEPS power cable for CPU power measurements until now is quite frankly baffling, and I'm extremely happy they've changed this.
Of course there are also questions of variability due to motherboards implementing different boost schemes, MCE, PBO, and so on differently for different chips. If you look at the most recent TPU CPU reviews, you'll see there's little variance between the 144W PPT Zen3 CPUs (5900X, 5950X), with the 138W 5800X sitting slightly below, and the 88W 5600X quite a bit below that again - though there is some variability due to this testing using a real world application (Blender) rather than a synthetic(-like) power virus/power draw generator like Prime95 or something else spawning nT of identical worker threads. Doing
actual work will always differ somewhat from synthetics
, but what you will see is that none of these exceed their PPT limits, which is AMD's spec.
AMD already admitted that they downclocked due to platform limitations.
Those "platform limitations" are specifically the lack of a separate voltage plane for the cache die, and not something relating to overall power draw or anything like that. It's just the simple fact that the L3 cache on AM4
must be on the same voltage plane as the core, and when the 3D V-cache can't handle above 1.35V, then the cores can't be fed more than that either. It has nothing to do with the platform not handling the power draw of a higher clocked X3D CPU - heck, the 5800X3D consumes
a lot less power than the regular 5800X.
This is already an admission of a big negative.
It's a drawback, sure, but "a big negative"? Nah. Just a minor annoyance that's extremely understandable when you introduce a brand-new feature like that on a 4th-gen product on the same platform. You don't design a platform with a bunch of spare voltage planes just because a future product might possibly need them at some point.
And again, the AM5 has more power headroom and therefore the 3d cache parts could be clocked higher than the non 3d cache parts.
This is a misunderstanding, see above. The 5800X3D is in no way held back due to power draw limitations of the platform. You seem to have missed out on some crucial information regarding these platform limitations which is leading you to think they are something entirely different from what they actually are.