Question [Phoronix] Ryzen 9 3900X vs. Ryzen 9 3950X vs. Core i9 9900KS In Nearly 150 Benchmarks (Linux)

DrMrLordX

Lifer
Apr 27, 2000
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Interesting. Usually the Phoronix test suite is biased enough towards ST performance that higher-core-count options don't shine all that much.
 

Makaveli

Diamond Member
Feb 8, 2002
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Viewing the graph for some reason or another I picture the center as a wagon train surrounded by hostile Indians....Maybe because AMD is the red team?

When invading someone's land you would be hostile too :)

I found the review to be good and nice to see non windows testing. And the 3900X winning some of the benches due to clock speed was also a surprise.
 

Atari2600

Golden Member
Nov 22, 2016
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The variability of performance between 3900X and 3950X is a bit surprising - and somewhat concerning given the very consistent advantage the 3950X is plotted up to hold over 9900KS.


I didn't really see an explanation why - which would leave me wondering what caused it. Some mix of throttling & Ahmdal? Or Silicon lottery? Or was it test procedure?
 

DrMrLordX

Lifer
Apr 27, 2000
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I didn't really see an explanation why

A 3900x can sustain clocks north of 4 GHz on "real world" workloads that have 24t or more. A 3950x will (sometimes) downclock as far as 3.5 GHz, though I don't have one on-hand to test. Theoretically, if a 3950x downclocked to 3.5 GHz on a 24t workload, the 3900x would be faster. Boost algorithms should make that impossible, but as we all know, AMD's boost algorithms took a long time to "get right" via AGESA updates. The 3950x may still need some work.
 

Topweasel

Diamond Member
Oct 19, 2000
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Yeah, I would have also expected the 3900X to be a smooth curve, like the 3950X.
The 3900x has a more boost range. It doesn't cap power limits til 10 cores and 12 cores is still within 10-20w of that. Means it has large range in boost behavior from 8-12 core loads (and as someone mentioned can maintain for some time a 4GHz boost all core). Due the extra power usuage of 33% more cores the 3950x starts balancing clocks and sustaining performance much earlier in the process which I think causes it to maintain a more uniform profile.