(anecdotal evidence: the ~140W package TDP I observe with Prime95 on a 6-core (analogous to the 6850K) is just about right for 178W total system power at 80% efficiency, so their numbers ring true here. I just ran another Prime95 SmallFFT test and I came up with 133W package TDP on HwMonitor64.)
Basically AMD is low-balling their TDP here (they rated the TDP for like 1-2 core loads with maybe a mild load on the other cores, is the official word IIRC) and Intel is high-balling their TDP, something like mixed-allcore with a decent amount of AVX thrown in.
In practice: both 8-core processors at default clocks are around 125W at a full normal (non-AVX) workload. Both 8-core processors are around 200W with an aggressive overclock. The 6900K tends to win modestly in most cases in either scenario (CineBench is like AMD's best-case). The general take was that the 1800X was a win on price vs the 6900X, not an overall win on performance or efficiency.
To sum up, the processors are within 10% power consumption on any given workload which is pretty much neck and neck as far as I'm concerned (normal variability). It's a good result for AMD given their Bulldozer track record but it's not an obvious win in efficiency. Again, of course the picture for server chips at 2.5 GHz might look very different than the picture at 4 GHz but that's speculation.
I don't know how well I trust your sources. Tom's Hardware shows typical 1-7% idle load for a Windows machine using Ryzen 1800x is about 14 watts. And your link shows power consumption idle for the same Windows at 70+ watts from .bit-tech.net and the other pcper shows almost 40watts. So you can see how that's a little contradictory. To be clear Tom's Hardware notes the numbers are for cpu only - not sure about your links.
The problem is that most PSUs have really terrible low-end efficiency. 80-Percent Plus's efficiency standards only kick in at 20% load, so the 1500W PSUs in the test systems sites use (eg your link - Silverstone ST1500) are massive overkill and you're running them at like 1% load. At those levels efficiency trails off to pretty much nothing - there is more or less a constant load at very low levels (i.e. efficiency approaches 0% near 0W load)
Looking at package-TDP only gives you a totally different picture. Not invalid necessarily - but different. It's easier to tease out the system under test but it's more difficult to get a holistic picture.
(As such, it is much much easier to cook the books when all you have to do is lie through a sensor readout than when you have to lie to a meter at the power plug. This is usually a game that gets played with GPUs, i.e. how the RX 480's "GPU-only" TDP excludes power consumption from memory, losses to VRMs, etc)
Also - servers are pretty much never at 0% load. Any system that has CPUs at 0% load consistently was over-allocated in the first place. Ryzen does idle a little bit better than Broadwell-E - although factoring out the PSU inefficiencies near the zero bound it's probably more like 25W for Broadwell vs 15W for Ryzen.
Right now HwMonitor64 says my 5820K is idling at the desktop at 25W FYI - "as reported by the CPU".
Do you have a source for this?