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
Full Load
Full Load
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)


View All Comments

  • 29a - Friday, February 14, 2020 - link

    It blows me away that you consider yourself an expert but use the term Windoze. I bet you use M$ too. Reply
  • msroadkill612 - Monday, February 10, 2020 - link

    Intuitively, turning off SMT seems an attractive option for many - for now anyway. For an extra $2k, you turn 64 threads into 64 cores, avoid some software issues & presumably get better utility from expensive memory. Reply
  • Silma - Monday, February 10, 2020 - link

    Can we still categorize a processor purchase as "Enthusiast" when it costs $3,990 ?
    Especially when the only reason to purchase it is 3D rendering?

    I don't think so. We need a new category and it's probably "Pro 3D renderer".
  • Pessimism - Monday, February 10, 2020 - link

    Can it run Crysis? Reply
  • Mugur - Tuesday, February 11, 2020 - link

    Yes, see LTT video. In software. Reply
  • XiZeL - Tuesday, February 11, 2020 - link

    Doesnt the Ryzen 9 3950X have 64Mb L3 cache? the table states 32Mb Reply
  • 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 Reply
  • Betonmischer - Tuesday, February 11, 2020 - link

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

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