The 64 Core Threadripper 3990X CPU Review: In The Midst Of Chaos, AMD Seeks Opportunity
by Dr. Ian Cutress & Gavin Bonshor on February 7, 2020 9:00 AM ESTFrequency, 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.
Facebook
Twitter
RSS
279 Comments
View All Comments
msroadkill612 - Sunday, February 9, 2020 - link
It has long puzzled me, that debate seems premised on unchangeable software, when of course few things are more readily changed.To say little software uses 128 threads is hardly surprising, when it is such a large increase to an unprecedented level.
Even if the extra threads have limited current utility, surely they are nice reserve resources to have as a likely upgrade path.
nt300 - Sunday, February 9, 2020 - link
You need to bring the Cores to market to push software developers into utilizing such horse power. Intel won't do that, because they rather overcharge for very little where as AMD has the upper hand and can add as many cores as possible. More Cores is where AMD can compete in, on top of providing a much better micro architecture.msroadkill612 - Monday, February 10, 2020 - link
my fault not making my point better - this is but one example of the mindset i refer to. "current benchmarks show x better than y, so buy x", even when y has far better fundamentals and its a very dynamic ecosystem.PCIE 4 gpu is a current maddening example. It is barely mentioned when comparing a multi year life span product (nvidia vs navi on x570) for an ecosystem clearly headed for exceeding current gpu cache levels.
dwade123 - Monday, February 10, 2020 - link
64 cores of uselessness is only good for servers. There ain't gonna be time for future software to make use of 128 threads either because tomorrow's software will shift to the GPU for AI and superior performance.msroadkill612 - Tuesday, February 11, 2020 - link
You mean like "nobody needs more than 4 cores"?Never say never.
nt300 - Sunday, February 9, 2020 - link
Once again AMD demonstrates aggressive innovation & technological advancements. Now that a set of ZEN engineers moves over onto the RTG, can't wait to see how well they fair with the RDNA2 enhancements.Redstorm - Monday, February 10, 2020 - link
It blows me away as a technologist that you tested this on Windoz, Unlock the potential with a true performance OS like Linux29a - 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.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.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".