Intel's recently introduced Xeon W9-3495X processor packs 56 cores begging you to overclock them, as the CPU also features an unlocked multiplier. When cooled down using liquid nitrogen, the 56-core processor can indeed be pushed to a formidable 5.50 GHz frequency, but at such high clocks it alone consumes almost 1,900 watts, more than beefy high-end gaming PCs, reports HardwareLuxx.
Elmor, a professional overclocker who collaborates with Asus, recently tried to push a Xeon W9-3495X 'Sapphire Rapids-SP' CPU on an Asus Pro WS W790E Sage SE motherboard to its limits with liquid nitrogen cooling. When frozen to -92.8 degrees Celsius/-135 degrees Fahrenheit, the CPU can work at 5.50 GHz and hit 132,220 points in Cinebench R23, which is just a little bit lower than the absolute record of 132,484 points set by another heavily overclocked Xeon W9-3495X. But the result comes at a cost.
The heavily overclocked Intel Xeon W9-3495X processor not only demonstrates phenomenal performance in Cinebench R23, but it also sets record in terms of power consumption. The CPU draws as much as 1,881W power when operating at 5.50 GHz and requires two 1,600W PSUs to feed it.
For comparison, Intel's previous-generation Core X-series processors with up to 18 cores could consume around 1,000W, whereas Intel's extreme workstation-oriented 28-core Xeon W-3175X drew up to around 700W when heavily overclocked and cooled down using various exotic methods.
Without any doubts, hitting 5.50 GHz with a 56-core Xeon W9-3495X processor cooled down using liquid nitrogen is a monumental achievement. Yet, it remains to be seen what makers of boutique factory-overclocked extreme workstations manage to squeeze out of this CPU with a production-grade cooling system and guaranteed long-term stability.
The 13900k uses 32W for single thread load although it runs higher clocks, the 7950x uses 43W
That's actually really efficient considering the extreme ends of the spectrum we're inhabiting here.
The main thing to remember is that these are Golden Cove cores (except with more L2 cache) and should be using the same process node as Alder Lake. So, we should be able to look to it for some idea of what's possible.
That's right: 78 W package power on one core! That Alder Lake CPU can use 35 W/core on 5 P-cores or about 33 W/core on 6 P-cores. With 7 P-cores, it's down below 30. That's one way to look at it, at least. I don't really look at 8, since it's whacking into the power limit by then.
Perhaps a more constructive way, that could account for a lot of the overheads, would be to look at the delta between 2 P-cores and the 1 P-core case. There, we see an increase of just 33 W. So, that suggests that a marginal power of 33 W/core is indeed what at least the stock K would boost up to. So, there actually might not be much more gas in the tank.
I'm less interested in the question of "badness", however. We all know this is well above the peak-efficiency point, as it's about 3x or more than what Sapphire Rapids or Genoa server CPUs are spec'd to run at. So, it's obviously bad, if you're efficiency-minded, but that wasn't the point of the experiment.
I think you're comparing apples and oranges here. A 7950x will not use 16x43 watts - that's 688 watts. But for a single core - yes, 43w is maybe right. This server chip OTOH, we're talking 33watts per single core. The number 33 watts popped up with one poster doing 1900/56 and getting 33 (actually it's almost 34). I assume it's only for a short bursts, or I'll be really interested in the cooling used :)
The other conclusion we might draw is that MP3 encoder is rubbish at showing the max sustained single-threaded power draw. I think this is definitely a factor, and probably the dominant one.
Here's the single-threaded data from Toms' review of the i9-13900K:
Source: https://www.tomshardware.com/reviews/intel-core-i9-13900k-i5-13600k-cpu-review/4It's at least closer to the Anandtech PovRay data, but still a wide gulf exists. Sadly, I haven't found anyone else testing these CPUs with PovRay @ 1 thread.