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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  • chrkv - Tuesday, February 11, 2020 - link

    What Windows version were using? I see claims that since version 18362.535 Windows 10 shows 1 socket for 3990X - look for "18362.535" here https://translate.google.com/translate?hl=&sl=... Reply
  • Betonmischer - Tuesday, February 11, 2020 - link

    That's right. Here's a proof that it does:

    https://imgur.com/G2VqgoU
    Reply
  • 29a - Friday, February 14, 2020 - link

    AT can't be bothered by the little stuff like OS patches when they're doing an AMD review. Haven't you seen any of their AMD launch reviews, they screw every one of those up. Reply
  • TokyoQuaSar - Wednesday, February 12, 2020 - link

    Very interesting article, I hope you can update it with data from an Epyc 77xx (7702 or 7742). Would be nice to have a head to head comparison, if possible a test with equal frequencies and some tests on software that are very dependant on memory bandwidth, to see the influence of the 8 channels aside from the amount of memory. Reply
  • vivs26 - Wednesday, February 12, 2020 - link

    Are there any linux distros for desktop that support more than 64 cores? Reply
  • TokyoQuaSar - Thursday, February 13, 2020 - link

    Not sure exactly but this test was done on Ubuntu and they don't mention any problem coming from the OS but rather from the tested software:
    https://techgage.com/article/amd-ryzen-threadrippe...
    They do say the number of cores scale better on Linux.
    Reply
  • HikariWS - Thursday, February 13, 2020 - link

    Very nice article! I've finally seen use cases where high core count counts!

    Indeed you should start adding some Lix benchs, I wonder how the kernel itself would handle that many cores. And of course M$ has to fix at least Pro Workstation.

    I'd rly like to see a review comparing HT enabled and disabled, around 8C. Is it worth disabling or enabling HT on my 9900KS? Under full load, is there difference in performance and consumption?

    How much performance the virtual cores have over physical ones? Do work load on one type affect the other? If we force affinity on one and leave its pair idle, and then put a full work load on it, how the tested core performs?
    Reply
  • HikariWS - Thursday, February 13, 2020 - link

    Still, I'm worried with AMD.

    Increase clock has been much harder than increase core count. AMD is very aggressive on core count, yes, but has been struggling on clock.

    9900KS is Intel's top notch on this regard. I can assure from personal tests how awesome it is. It idles @ 45º in a Noctua D15S. With Prime95, goes to 80º and holds 5GHz All Core for a few minutes before dropping to 4GHz and holds that undefinitely.

    In real world use, specially gaming and 4K playback, it's able to hold 5GHz undefinitely, I haven't seen its Turbo juice depleat not even once! For anybody who doesn't need more than 8C/16T and benefits more from serial processing, it's the best of the best, and I doubt Comet Lake will bring a competitor to it.

    Intel has been increasing cores in response to Intel, and with exceptions they have been winning in overall performance against AMD CPUs with more core count.

    In the future years we'll face algorithms struggle to scale in parallelism. Most softwares don't benefit from more than 4 or 8 threads, and be allocated to a virtual HT core just reduces opportunity to perform better. When we reach software optimization limits, increasing core count won't benefit users anymore, and we'll face increased demand for serial power.

    Then we go for microarchitecture. AMD are on their brand new one, while litography issues is holding Intel from widely distribute their Sunny Cove, and they are close to finishing their Willow Cove. When Intel finish their 7nm, they will have 2 more powerful microarchitectures to bring to desktop and server market, while AMD is working on their future one.

    Summing that up, I believe in a few years Intel will have consistent performance growth over their generations, while AMD will start struggling.
    Reply
  • kuraegomon - Tuesday, February 18, 2020 - link

    Oh dear. Intel shill confirmed. What makes me so confident? "Most softwares don't benefit from more than 4 or 8 threads" - anyone who makes that statement in 2020 with the implication that it's a forward-looking statement is clearly being disingenuous. Reply
  • clsmithj - Thursday, February 13, 2020 - link

    Should added Linux to the benchmark graph comparison Reply

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