Frequency, Temperature, and Power

A lot of questions will be asked about the frequency, temperature, and power of this chip: splitting 280W across all the cores might result in a low all-core frequency and require a super high current draw, or given recent reports of AMD CPUs not meeting their rated turbo frequencies. We wanted to put our data right here in the front half of the review to address this straight away.

We kept this test simple – we used our new NAMD benchmark, a molecular dynamics compute solver, which is an example workload for a system with this many cores. It’s a heavy all-core load that continually cycles around the ApoA1 test simulating as many picoseconds of molecular movement as possible. We run a frequency and thermal logger, left the system idle for 30 seconds to reach an idle steady state, and then fired up the benchmark until a steady state was reached.

For the frequencies we saw an ‘idle’ of ~3600 MHz, which then spiked to 4167 MHz when the test began, and average 3463 MHz across all cores over the first 6 minutes or so of the test. We saw a frequency low point of 2935 MHz, however in this context it’s the average that matters.

For thermals on the same benchmark, using our Thermaltake Riing 360 closed loop liquid cooler, we saw 35ºC reported on the CPU at idle, which rose to 64ºC after 90 seconds or so, and a steady state after five minutes at 68ºC. This is an ideal scenario, due to the system being on an open test bed, but the thing to note here is that despite the high overall power of the CPU, the power per core is not that high.


Click to zoom

This is our usual test suite for per-core power, however I’ve condensed it horizontally as having all 64 cores is a bit much. At the low loads, we’re seeing the first few cores take 8-10W of power each, for 4.35 GHz, however at the other end of the scale, the CPUs are barely touching 3.0 W each, for 3.45 GHz. At this end of the spectrum, we’re definitely seeing AMD’s Zen 2 cores perform at a very efficient point, and that’s even without all 280 W, given that around 80-90W is required for the chipset and inter-chip infinity fabric: all 64 cores, running at almost 3.5 GHz, for around 200W. From this data, we need at least 20 cores active in order to hit the full 280W of the processor.

We can compare these values to other AMD Threadripper processors, as well as the high-end Ryzens:

AMD Power/Frequency Comparison
AnandTech Cores CPU TDP   1-Core
Power
1-Core
Freq
Full Load
Power/core
Full Load
Freq
3990X 64 280 W   10.4 W 4350 3.0 W 3450
3970X 32 280 W   13.0 W 4310 7.0 W 3810
3960X 24 280 W   13.5 W 4400 8.6 W 3950
3950X 16 105 W   18.3 W 4450 7.1 W 3885

The 3990X exhibits a much lower power-per-core value than any of the other CPUs, which means a lower per-core frequency, but it isn’t all that far off at all: less than half the power for only 400 MHz less. This is where the real efficiency of these CPUs comes into play.

The 64 Core Threadripper 3990X CPU Review The Windows and Multithreading Problem (A Must Read)
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  • sharath.naik - Saturday, February 8, 2020 - link

    Agree, for a 64 core processor to be fully utilized you need more ram capacity. But we do have 64gb rams already available which means that you can go up to 512GB today. It is an unnecessary limitation. Reply
  • antus - Sunday, February 9, 2020 - link

    It still has use for scientific workloads. Its up to the user to decide if this many cores in this configuration at this low price works for them.
    Its a pitty this article centered so much on windows limitations. Sure some people might want this many cores in a HEDT configuration but i'd like to see linux benchmarks due to it being a free OS that can handle this cpu properly and run scientific workloads. It likely would have a place in the racks of university where I work.
    Reply
  • GreenReaper - Sunday, February 9, 2020 - link

    Ultimately this is a Windows shop, you need to look to Phoronix or ServeTheHome (which did both). Takeaway is the same but they do more traditional server workloads. For parallel sever tasks, it's great. Most people will want to use one of the cut-down CPUs and use the savings on for RAM/storage. Reply
  • kardonn - Tuesday, February 11, 2020 - link

    I run a very high end VFX studio and do simulation work for big features, high end commercials, and big productions for Amazon/Netflix. I assure you, 256GB RAM is way more than I've ever needed and will easily be futureproof enough until larger UDIMMS become available one day to unlock the 512GB potential.

    All of my current workstations are 128GB of RAM and it's very rare for me to work on jobs that even approach that limit. 256GB is tons for 99% of the work people will be throwing a 3990X at.
    Reply
  • Santoval - Sunday, February 9, 2020 - link

    It depends on how you define "enthusiasts". If you mean enthusiast *creators* who need a workstation for their work then sure, that's the CPU for them. Video editors, photographers, graphics designers, industrial designers, game designers ... these kinds of creators. It's not just for playing games or merely running benchmarks though. Even for a professional musician it might be overkill. Reply
  • WaltC - Friday, February 7, 2020 - link

    I found this article a bit baffling, frankly. I did not understand the "out of chaos" titling at all...;) But anyway--it should be obvious what AMD is doing here--people running desktops for gaming running Win10 home or Pro are *not* the people the CPU is aimed at--the CPU is aimed at Prosumers who would rather not spend $20k for Intel's inferior solutions but would rather spend $4k for a faster cpu solution and save a cool $16k in the bargain and come out with something appreciably faster. Yes, people are going to run this with Enterprise--duh...;) You aren't going to spend money on a 128t cpu and then run it with a 64t OS--don't even know why Win10 and Win10 Pro were mentioned at all--other than to state they shouldn't be used with the CPU--which would take but a single sentence. Then there the handful of benchmarks used here--how many threads do each of these benchmarks support at maximum? Article didn't say--so that was sort of a strike out, etc. I think Anandtech needs to come back and do this review properly--as it stands, this one makes it seem like the only "chaos" involved is the obvious confusion in the minds of the AT reviewers....;) (No offense) Simply put: if Intel couldn't sell $20k cpu systems Intel wouldn't make them--so obviously, there's a market for 128t cpus--again, duh. You can do much better than Intel at a fraction of the cost--and there's your market! No chaos at all. Also: this CPU is very new--there remain the usual AGESA bios improvements that need to be made in the upcoming months, etc. That fact should have garnered at least a sentence, don't you think? In the past I've seen much better reviews than this--especially for the world's first and only 128t single CPU! Reply
  • WaltC - Friday, February 7, 2020 - link

    Above I meant to say that "In the past I've seen much better reviews from AT,"--you guys going to get a decent editing system for the news section anytime soon? Reply
  • Irata - Friday, February 7, 2020 - link

    Good point. Check OEM workstations like the Dell Precision 7920 and what is the installed OS ? Windows 10 for workstations. And that's for the lowest end 6C6T Xeon Bronze model.

    The OS version's name kinda gives it away.
    Reply
  • Irata - Friday, February 7, 2020 - link

    You could use a car comparison test as an analogy: if you are comparing a two seater to a sedan and your conclusion is that the sedan's passenger seat is more spacious, you are missing an important point - the sedan has space for three passengers, the two seater only for one, i.e. you can do things with the sedan that you cannot with the two seater. Reply
  • 29a - Friday, February 7, 2020 - link

    They always halfass AMD reviews, just look at EVERY Ryzen release. Reply

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