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ajlueke
Grandmaster

AMD announces 16-core Ryzen 9 3950X. Available in September. Update, Available in November.

All core clock of 3.5 GHz with a boost frequency of 4.7 GHz.  105W TDP.  It will be interesting to see how latency is affected for core-core communication with multiple chiplets.  Both the R9 models sport multiple chiplets.

https://www.anandtech.com/show/14516/amd-16-core-ryzen-9-3950x-up-to-4-7-ghz-105w-coming-september

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With the dedicated I/O chiplet in this generation as well as reduced L1 cache we know latency is going to be both consistent and higher than Zen and Zen+ from Lisa Su's speech at E3, so that combined with the new Windows 10 scheduler should eliminate those cross CCX issues Zen suffers with.

But with 16 cores, no doubt there will be issues like there are with high core count Threadrippers in some programs...

David_McAfee-Next_Horizon_Gaming-3rd_Gen_Ryzen_06092019-page-009

David_McAfee-Next_Horizon_Gaming-3rd_Gen_Ryzen_06092019-page-008

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The Ryzen 9 3900X certainly seems to be the sweet spot in price/performance.  For $100 over the R7 3800X, you get 4 additional cores ($25 per core).  The next 4 core jump to the R9 3950X costs $250 ($62.50 per core).  Jumping from a Ryzen 5 3600X to a 3700X costs $80 (or $40 per core). 

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That I would agree with, plus finding a program that would make use of an extra 4 cores and justify the extra $250 expense on a platform with only a dual channel memory controller would be an issue, not to mention the overall lower operating frequency as the 3800X-3950X share the same 105w TDP.

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ajlueke
Grandmaster

So it sounds like the jump in price for those last four cores is due in part, due to special binning on the R9 3950X.  

The R9 3950X is intended not only to have the highest core count, but also the highest single threaded performer.  AMD wants to ensure that both creative and gaming performance increase as you move up the product stack.

https://www.google.com/amp/s/www.pcgamesn.com/amd/ryzen-9-3950x-best-gaming-cpu%3famp 

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I think the implication is that the parts with the most cores, will also have the highest single core boost clocks.  Unlike Intel where the higher core parts typically clocked lower than the mainstream parts, making the mainstream parts better for gaming.

So if you buy a R9 3950X it will be the fastest AM4 part in productivity and content creation (more cores) but also in gaming (highest boost clock).

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ajlueke
Grandmaster

So...It's September.  Maybe they are waiting for the UEFI boost clock fix to drop the 3950X so it hits 4.7GHz for reviewers.

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Or TSMC is having a huge yield problem and AMD is devoting as much as possible to the EPYC server line as they command much, much higher prices.

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ajlueke
Grandmaster

Looks like September 30th may be the day.  About the time that the 1.0.0.3ABBA UEFI releases should be available for reviewers.

https://www.techradar.com/news/amd-ryzen-9-3950x-release-date-may-be-incoming

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I saw that the other day, but when I checked Digitech, they changed to "delivery date unknown", granted it is being released at the end of the month. Also hope that €999 price is a placeholder...

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Regardless of the price, I expect the initial shipments will be lost to scalpers within the first 5 minutes of release and promptly reposted on eBay for a 30% markup. 

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I'm not so sure this time. Given the issues some programs have with CPUs with 16 or more cores, and given the fact that it only features a dual channel memory controller and far fewer PCIe lanes than Threadripper, and higher heat generation under a smaller surface area to dissipate... Under Blender and under air the 3900X already reaches 79*C. Given there is a 13*C jump from the 8 core 3700X to the 12 core 3900x, and the fact the 3950X is rated for the same speeds as the 3900X while adding 33% more active cores, that's going to be pushing the mid 80s, and is going to seriously limit the boost function (and nobody knows what the full core boost will be). I wouldn't be surprised if the 3900X ends up either being the faster CPU or only a couple of percent slower in real world usage because of these facts. Then you factor in the $200-$250 price premium on top of the 3900X (assuming launch price of the announced $750), it becomes a much harder sell.

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It isn't rated at the same speeds.  The 3950X has a base clock of 3.5 GHz, vs 3.8 GHz for the 3900X.  That is to keep it within the same TDP as the 3900X (105W).  All AMD 105W processors have the same socket power limitation of 142W, which  would be the maximum amount of heat you have to dissipate.  Naturally, the 3700X generates less heat, it is a 65W TDP processor.  Given that the 3950X is still a 105W processor, it will have the exact same 142W socket power limitation as the 3900X, meaning their won't be more heat to dissipate.

Ramping up 16 cores vs 12, the 3950X will hit power/current/voltage limits at lower clockspeeds than the 3900X, hence the 3.5GHz base clock as opposed to 3.8GHz.

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ajlueke
Grandmaster

Taken from Forbes.

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Not sure if I buy AMDs explanation.  The only SKU of Zen 2 that has been consistently unavailable is the 3900X.  That chip uses 6 core CCDs vs 8 on the 3950X.  So maybe they need 8 core CCDs to boost 3700X and 3800X stock?  One would think those 8-core CCDs that can hit 4.7 GHz would only be used for 3950Xs.  

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I think it's a combination of things AMD doesn't want to admit. Yields are quite likely lower than expected meaning the number of flawless chiplets are few, demand for 7nm chips from other companies is taking fab time as TSMC just announced a tripling of the length of lead time for 7nm chips, EPYC processors are undoubtedly taking up a large part of AMD's chiplets as a number of them have already been presold so flawless chiplets may be being reconfigured and used there instead of Ryzen and upcoming Threadripper processors, and there's also the distinct possibility that AMD may be laser cutting fully functional chiplets and using them to make the 3800X and lesser processors due to the fact those chips have much higher mass market appeal, and the smart thing for AMD at this point is still to target the consumer mainstream to take market share from Intel.