# Ryzen 3000 memory controller has "half the performance" on single CCD CPUs



## TheLostSwede (Jul 8, 2019)

This is an interesting observation that I had missed until now.
It would appear AMD has "cheaped out" on their memory controller a bit and it only has "half the performance" on CPUs with only one CCD in them, during write operations.
Seemingly it has little affect in most applications, but if you're doing something that does a lot of intensive memory writes, you might want to consider getting a dual CCD CPU.
It does seem to have a small affect on the memory latency though.
Just a heads up, as it was not something that was particularly clear from AMD's side.






Source: https://www.guru3d.com/articles_pages/amd_ryzen_7_3700x_ryzen_9_3900x_review,21.html


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## biffzinker (Jul 8, 2019)

TheLostSwede said:


> It would appear AMD has "cheaped out" on their memory controller a bit and it only runs at "half speed" )16 vs 32-bit) on CPUs with only one CCD in them


It's 64Bytes/Cycle when reading from memory but drops down to 32Bytes/Cycle for writes. A review somewhere mentioned it.


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## TheLostSwede (Jul 8, 2019)

I guess the source link got it slightly wrong, but yeah, still half speed for writes on single CCD CPUs.


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## Flaky (Jul 8, 2019)

32 bytes * 1666 megahertz = 57.6  GBps

As long as each arrow is not a sum of 16B/cycle in each direction, a single CCD should have enough bandwidth to handle dual channel throughput.

My educated guess is that for some reason in this test the IF divider got set to 1:2.


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## londiste (Jul 8, 2019)

DRAM:FSB ratio on AIDA screenshots is 54:3 for both, should that reflect the divider?
If they switch different CPUs around leaving divider could happen by mistake, I suppose.


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## biffzinker (Jul 8, 2019)

TheLostSwede said:


> I guess the source link got it slightly wrong, but yeah, still half speed for writes on single CCD CPUs.


The reason for the 32B/cycle writes was explained as they happen less often than reading from memory.

Anyone up for a deep dive into the Zen 2 core?








						A Look At The AMD Zen 2 Core
					

Ahead of the highly anticipated Ryzen 3000 desktop series launch, here is a look at the AMD Zen 2 core microarchitecture.




					fuse.wikichip.org


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## TheLostSwede (Jul 8, 2019)

biffzinker said:


> The reason for the 32B/cycle writes was explained as they happen less often than reading from memory.
> 
> Anyone up for a deep dive into the Zen 2 core?
> 
> ...


Which sort of makes sense, but it also makes the single CCD CPUs look "bad" in some synthetic benchmarks. It doesn't seem to make much of a real world difference though and even the latency difference seems to be a mostly moot issue, if there even is a difference, since I've seen other tests that shows none.


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## biffzinker (Jul 8, 2019)

TheLostSwede said:


> latency difference seems to be a mostly moot issue, if there even is a difference, since I've seen other tests that shows none.


The Zen2 L3 Cache Latency is up compared to Zen+, and memory latency is a touch higher.









			
				Anandtech said:
			
		

> In terms of the DRAM latency, it seems that the new Ryzen 3900X has regressed by around 10ns when compared to the 2700X (Note: Just take into the leading edge of the “Structural Estimate” figures as the better estimate) with ~74-75.5ns versus ~65.7ns.
> 
> It also looks like Zen2’s L3 cache has also gained a few cycles: A change from ~7.5ns at 4.3GHz to ~8.1ns at 4.6GHz would mean a regression from ~32 cycles to ~37 cycles.


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## londiste (Jul 8, 2019)

L1 and L2 are pretty much even. L3 Cache latency is slightly up but there is also twice as much L3 Cache. Memory latency is simply an inevitable tradeoff of chiplet design.
Overall it is still a noticeable improvement.


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## Octopuss (Jul 8, 2019)

What is a CCD CPU?


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## Ferrum Master (Jul 8, 2019)

Octopuss said:


> What is a CCD CPU?


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## biffzinker (Jul 8, 2019)

Octopuss said:


> What is a CCD CPU?


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## TheoneandonlyMrK (Jul 8, 2019)

TheLostSwede said:


> This is an interesting observation that I had missed until now.
> It would appear AMD has "cheaped out" on their memory controller a bit and it only runs at "half speed" on CPUs with only one CCD in them, during write operations.
> Seemingly it has little affect in most applications, but if you're doing something that does a lot of intensive memory writes, you might want to consider getting a dual CCD CPU.
> It does seem to have a small affect on the memory latency though.
> ...


Halfs performance, not speed , they run at the same speed but with one less ccd doing 16b writes that's half the writes and reads coincidentally since that one ccd can't read as much as two.


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## TheLostSwede (Jul 8, 2019)

theoneandonlymrk said:


> Halfs performance, not speed , they run at the same speed but with one less ccd doing 16b writes that's half the writes and reads coincidentally since that one ccd can't read as much as two.


Right, yes. Edited the titles to make that more obvious.


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## EarthDog (Jul 8, 2019)

We caught that in testing and was in the review.. I don't think it matters much, however.

Hearing "CCD" brings me back to Catholic school/baptism/confirmation days... lol


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## TheLostSwede (Jul 8, 2019)

EarthDog said:


> We caught that in testing and was in the review.. I don't think it matters much, however.
> 
> Hearing "CCD" brings me back to Catholic school/baptism/confirmation days... lol



It doesn't seem to matter much in 99% of applications, that's for sure, at least judging by the benchmarks. It was just one of those things I really hadn't realised they'd done.
Admittedly it's right there in their presentations (if you compare 1x CCD vs 2x CCD CPUs), but they obviously didn't highlight it, for reasons.
It just something worth getting out there for those 1% scenarios that people might run and they might be surprised why the performance suffer.


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## birdie (Jul 8, 2019)

Yeah, I've also noticed that: https://forums.anandtech.com/threads/ryzen-3700x-low-ram-write-speed-conundrum.2567215/


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## Vario (Jul 8, 2019)

Can the IO Die be overclocked?


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## Wavetrex (Jul 8, 2019)

This is basically like an old "dual-cpu + northbridge" design inside a small box, with bus speeds updated to modern day.

I remember an old Dual Pentium III system that I used many years ago, it suffered from exactly same thing: Removing one CPU would half memory bandwidth, even if the memory was still connected to the same northbridge. The "FSB" from one single CPU simply couldn't keep up.
Old ....... New
Pentium "Core" = CCD
Intel FSB = AMD IF
I/O die = Northbridge (memory controller) + half of Southbridge

Tbh, as long as application performance is fine, this is a non-issue.


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## Vya Domus (Jul 8, 2019)

Vario said:


> Can the IO Die be overclocked?



Doubt it, everything on a chip that is outside the core/cache/MC usually runs at vastly different speeds and requires tight timing so that it can communicate with other chips and buses.


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## biffzinker (Jul 8, 2019)

EarthDog said:


> We caught that in testing and was in the review


You do reviews for who? Guru3D?


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## EarthDog (Jul 8, 2019)

biffzinker said:


> You do reviews for who? Guru3D?


It's a bit complicated... lol

I own a site and work for another, much larger site (YHPM).


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## TheLostSwede (Jul 8, 2019)

EarthDog said:


> It's a bit complicated... lol
> 
> I own a site and work for another, much larger site (YHPM).


Now now, no need to be so shy, I'm sure there won't be any hard feelings if you share with everyone...


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## mouacyk (Jul 10, 2019)

Hexus.net has similar explanation to Anandtech and Overclockers.uk:


> AMD says that this is a calculated design choice for Zen 2, due to most client workloads  not writing as much. Halving the data link write speed between CCD and cIOD saves area, improves power, and has ancillary knock-on benefits, too. The downside is half-write speed because of the slowness of the data fabric in that direction.



I'm more curious about the max bandwidth of IF at 1800MHz or 1900MHz (for capable silicon) and what this means for all data (especially PCIE) that needs to go through the IF.  I'm sure AMD has calculated it to be sufficient for all or most needs, but does anyone know any numbers?  Thanks.


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## clbc12 (Jul 10, 2019)

This is the exact discussion I've been searching desperately for for the past few days... I'm a VFX artist by day, indie filmmaker by night who needs to build a new PC for a personal project-- I've already bought all parts except CPU and need to complete the build ASAP, but I'm really worried about this whole "half the memory for writes" thing on the new Ryzen's, because I suspect CG animation filmmaking workflows will be a 1% sort of thing vs. who these processors seem to be built for (gamers, etc.).

I animate in 3D (Maya) 2D (After Effects), and edit in Premiere (though I may switch to Resolve soon). A huge part of my workflow is being able to play back previews of animation in real time (the less dropped frames, the better). I'm not terribly tech savvy and only build a workstation every 5-7 years, so it's hard for me to discern what involves writing to RAM vs. reading from it, but it seems to me that something we call "RAM previews" in AE would be writing to RAM, and I do that a lot, and really need it to be fast. Render/export speed is less important to me, as I do that far less often and can let my computer render while I'm doing other things. You guys seem to really understand a lot about this issue (I've had trouble finding people that do), so I'd appreciate it very much if you could tell me whether you think my workflow would improve or suffer if I went with, say, a 3600x vs. a 2600x, etc.? Thanks!


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## TheoneandonlyMrK (Jul 10, 2019)

clbc12 said:


> This is the exact discussion I've been searching desperately for for the past few days... I'm a VFX artist by day, indie filmmaker by night who needs to build a new PC for a personal project-- I've already bought all parts except CPU and need to complete the build ASAP, but I'm really worried about this whole "half the memory for writes" thing on the new Ryzen's, because I suspect CG animation filmmaking workflows will be a 1% sort of thing vs. who these processors seem to be built for (gamers, etc.).
> 
> I animate in 3D (Maya) 2D (After Effects), and edit in Premiere (though I may switch to Resolve soon). A huge part of my workflow is being able to play back previews of animation in real time (the less dropped frames, the better). I'm not terribly tech savvy and only build a workstation every 5-7 years, so it's hard for me to discern what involves writing to RAM vs. reading from it, but it seems to me that something we call "RAM previews" in AE would be writing to RAM, and I do that a lot, and really need it to be fast. Render/export speed is less important to me, as I do that far less often and can let my computer render while I'm doing other things. You guys seem to really understand a lot about this issue (I've had trouble finding people that do), so I'd appreciate it very much if you could tell me whether you think my workflow would improve or suffer if I went with, say, a 3600x vs. a 2600x, etc.? Thanks!


You should fill out your system specs in your profile, its helpful knowing where your coming from.
The thread title is completely wrong, the memory controller and memory are unaffected theoretically since these days other components can read and write to memory as well as the CPU and it is technically the link between the CPU cores and the io die/ memory controller not quite the same since a lot of other io uses that route.
If i were you though I would hold on a bit, someone will investigate this ,likely intel and any real issues will be found. I
Don't think it an issue but getting either the 3900x which isn't affected or threadripper or an Intel quad memory platform would provide an increase in memory bandwidth.
All this is my thoughts though and I'm holding onto my cash for now .


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## mouacyk (Jul 10, 2019)

clbc12 said:


> This is the exact discussion I've been searching desperately for for the past few days... I'm a VFX artist by day, indie filmmaker by night who needs to build a new PC for a personal project-- I've already bought all parts except CPU and need to complete the build ASAP, but I'm really worried about this whole "half the memory for writes" thing on the new Ryzen's, because I suspect CG animation filmmaking workflows will be a 1% sort of thing vs. who these processors seem to be built for (gamers, etc.).
> 
> I animate in 3D (Maya) 2D (After Effects), and edit in Premiere (though I may switch to Resolve soon). A huge part of my workflow is being able to play back previews of animation in real time (the less dropped frames, the better). I'm not terribly tech savvy and only build a workstation every 5-7 years, so it's hard for me to discern what involves writing to RAM vs. reading from it, but it seems to me that something we call "RAM previews" in AE would be writing to RAM, and I do that a lot, and really need it to be fast. Render/export speed is less important to me, as I do that far less often and can let my computer render while I'm doing other things. You guys seem to really understand a lot about this issue (I've had trouble finding people that do), so I'd appreciate it very much if you could tell me whether you think my workflow would improve or suffer if I went with, say, a 3600x vs. a 2600x, etc.? Thanks!


The one benchmark that was affected directly was SuperPI 32M.  I would imagine that anyone who uses RAM drives can benchmark this easily also.  For a single user, 22GB/s still seems to be plenty of bandwidth for any work you might be doing.  If you use a single-CCD ryzen 3000 to run (say) a VM for more than 2 people, then they will be doing RAM writes at DDR2 speeds all of a sudden which may be noticeable.


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## photonboy (Jul 10, 2019)

GUYS,
Don't bother looking at data that doesn't matter. Focus on real-world benchmarks. It reminds me of the graphics card troll saying "but this card has more VRAM bandwidth" when they completely missed the point that there was lossless data compression and the card was scoring higher in benchmarks anyway compared to the card they were trying to say was better...

If an R9-3900X scores higher in a benchmark for a program YOU USE then go ahead and get it. Don't even worry about the architectural reasons beyond knowing what DDR4 capacity, CL value etc to get


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## clbc12 (Jul 11, 2019)

Thanks for your help, everyone who replied! This was kind of what I was wondering, actually-- whether "memory write speed" actually means anything in the real world, or whether there are a ton of other factors at work that might make that one number irrelevant. So far only Puget Systems has done an After Effects or Premiere benchmark that I can find (and Blender, which is pretty similar to Maya), but I'm a tad concerned that most benchmarks for content creators seem to center around render and export times, when, in the real world, these numbers matter much less for most of us than how fast we can complete a RAM preview, or how many frames get dropped during playback in a Maya or Premiere timeline (which I think is a caching thing... I admittedly don't know much about how that works on the hardware end).

Here's a link to the Puget benchmarks, by the way... wish they'd talk about what goes into their "overall score" as it's harder to relate to real-world performance than, say, FPS number for gamers: https://www.pugetsystems.com/labs/a...MD-Ryzen-3rd-Gen-CPUs-for-Video-Editing-1522/

...from those benchmarks it would appear that the 3600 out-performs even the 2700x pretty massively, so maybe the memory write speed is something that doesn't matter at all in these programs.

Also, special thanks to the person who clarified that this means 22Gb/s can be written to RAM-- since RAW 4k video is, I think, 2Gb/minute of data, and most of what I work on is broken up into shots or sequences that are often nowhere close to a minute per section that needs to be previewed at a time, I can't imagine how, even with a lot of effects applied in AE or Premiere, etc. I could ever approach needing to load more than 22Gb/s into the RAM... so, I'm thinking the only possible real-world issues would be the potential multi-user scenario described.


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## Mr.Scott (Jul 11, 2019)

TheLostSwede said:


> Now now, no need to be so shy, I'm sure there won't be any hard feelings if you share with everyone...


Lol........no, I'm pretty sure there would be.


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## Wavetrex (Jul 11, 2019)

mouacyk said:


> I'm more curious about the max bandwidth of IF at 1800MHz or 1900MHz (for capable silicon) and what this means for all data (especially PCIE) that needs to go through the IF.


DRAM speeds are orders of magnitude faster than PCI-e.

Even full slot 16x PCI-e 4.0 maximum theoretical speed is 32GB/s ( 16 GT(transfers)/s per bit , x 16 = 256 GT / 8 = 32), and no GPU today or in the near future is capable of sucking up CPU data so fast.
A 4x NVMe drive is only 8 GB/s theoretical max, and even that "reduced" memory bandwidth on R7 3700x (measured at over 28 GB/s) is several times faster.

Also be aware that this is pure CORE to MEMORY transfer speed, that doesn't count DMA access

DMA = Direct Memory Access, a function of the "North Bridge" (Now called I/O Die) allowing PCI devices to read and write in memory WITHOUT the CPU.
Basically, the CPU only tells the DMA Controllers " Copy NNN pages from here to there", and then the DMA does it by itself, creating an interrupt message to the CPU when done.
During that time, the CPU is free to do other things...

Most GPU texture loads, or NVMe transfers take place via DMA, so the write bandwith of IF is meaningless in those situations. No bytes are actually moved into and out of the core/cache/CCD/CCX

This has been part of CPU architectures since EVER, even the original IBM PC had a DMA controller chip (called Intel 8237)





						Direct memory access - Wikipedia
					






					en.wikipedia.org
				




Of course, the DMA controller became faster and faster, and today it is integrated in the PCI-e fabric, so any PCI-e device can access memory or another PCI-e device (That's how CrossFire / SLI works actually, espcially CrossFire without a bridge), but it works for any PCI(e) device, including USB controllers, Network, SATA controller, ANYTHING actually.

So yea, stop worrying about Zen 2 memory write speed, it's a total non-issue.


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## Metroid (Jul 11, 2019)

On this review, aida memory write on 3700x seems okay, I wonder why.

*"CPU being tested*
AMD Ryzen 7 3700X (3.6GHz – 4.4GHz Boost) _Zen 2_

*TEST SETUP*

*Cooling* be quiet! Dark Rock 4
*Motherboard* MSI Prestige X570 Creation
*Memory* 32GB Corsair Vengeance LPX 3000MHz
*Graphics* Radeon RX 480 8GB
*Storage* Corsair LX 512GB SSD
*PSU* Corsair RM 1000 80 Plus Gold Certified PSU "
















						AMD Ryzen 7 3700X Review - Memory Transfer Performance  AIDA64
					

The recipe of 8-cores and 16-threads is well-established in the Ryzen lineup, but now we see it produced in an entirely different way on the brand new 7nm lithographic process. Welcome everyone to the Ryzen 7 3700X.



					www.vortez.net
				




Stepping cpu defect? It cant possibly be, can't it?


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## Vario (Jul 11, 2019)

Metroid said:


> On this review, aida memory write on 3700x seems okay, I wonder why.
> 
> *"CPU being tested*
> AMD Ryzen 7 3700X (3.6GHz – 4.4GHz Boost) _Zen 2_
> ...



Looks like decent performance, you have the latest bios?


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## biffzinker (Jul 11, 2019)

clbc12 said:


> Thanks for your help, everyone who replied! This was kind of what I was wondering, actually-- whether "memory write speed" actually means anything in the real world, or whether there are a ton of other factors at work that might make that one number irrelevant.


The memory copy bandwidth is up over Zen+, and comes close to tying with Intel's copy bandwidth. Might be one those other factors at work.


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## mouacyk (Jul 11, 2019)

Metroid said:


> On this review, aida memory write on 3700x seems okay, I wonder why.
> 
> *"CPU being tested*
> AMD Ryzen 7 3700X (3.6GHz – 4.4GHz Boost) _Zen 2_
> ...


Whoa O!  Makes me wonder if some 3700X are actually multi-CCD's with disabled CCX's?


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## Metroid (Jul 11, 2019)

Vario said:


> Looks like decent performance, you have the latest bios?



It's not me, it's this review's link https://www.vortez.net/articles_pages/amd_ryzen_7_3700x_review,13.html



mouacyk said:


> Whoa O!  Makes me wonder if some 3700X are actually multi-CCD's with disabled CCX's?



That is exatcly the problem, I dont know what the hell is going on, some 3700x is okay some no? It can't be the motherboard. I will try to find another review showing that.


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## Wavetrex (Jul 11, 2019)

mouacyk said:


> Whoa O!  Makes me wonder if some 3700X are actually multi-CCD's with disabled CCX's?


That is very possible and I had suspected that ever since the first leaks/rumors from Adored (many months ago) about using multiple dies.

The thing is, unless people start de-liding them en-masse, so those "4+4" 3700X-es are found, there is no way of knowing.
That memory bandwidth benchmark might be an indicator, but it's not proof.

This video is from DECEMBER last year, almost 2 months before even AMD showed that 1-chiplet + 1 IO die at CES









Yes, he got some of SKU "numbers" wrong, and obviously prices.... but that's all marketing.

What did he got right?
Let's see...




In his chart:
Ryzen 3 3300X - 6c ... 3.5 base, 4.3 boost ... became the 3600X : Base Clock 3.8GHz, Max Boost Clock 4.4GHz (better!) - https://www.amd.com/en/products/cpu/amd-ryzen-5-3600x
Ryzen 5 3600 - 8c ... 3.6 base, 4.4 boost ... became the R7 3700X: Base 3.6, Boost 4.4 (identical !!! just the name changed) https://www.amd.com/en/products/cpu/amd-ryzen-7-3700x
Ryzen 7 3700 - 12c ... 3.8 base, 4.6 boost ... became R9 3900X: Base 3.8, Boost 4.6 (identical !!!) https://www.amd.com/en/products/cpu/amd-ryzen-9-3900x
Ryzen 9 3800X - 16c ... 3.9 base, 4.7 boost !? ... "too good to be true" became known as R9 3950X: Base 3.5 (not quite), Boost 4.7 (identical)  https://www.amd.com/en/products/cpu/amd-ryzen-9-3950x

Now that the launch has happened, I am extremely surprised how ACCURATE the specs are, especially considering the MEASURED power consumption in the reviews, not the ones declared by AMD.
Variations in names of the products or prices DO NOT MATTER, as those can be changed from one second to another before launch.

Again, this was 7 (SEVEN) months ago !

Also, I seriously believe that AMD has targeted those frequencies for boost (4.8-5.1), but TSMC failed to deliver... and we got what we got.
It's very possible that once the process is improved there will be a refresh that adds 300-400Mhz to the clocks.


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## Metroid (Jul 11, 2019)

This post will be updated to reflect what I can find. For now these are the aida benchmarks that I found on reviews.

First will be images of reviews without aida write memory write issue.















						AMD Ryzen 7 3700X Review - Memory Transfer Performance  AIDA64
					

The recipe of 8-cores and 16-threads is well-established in the Ryzen lineup, but now we see it produced in an entirely different way on the brand new 7nm lithographic process. Welcome everyone to the Ryzen 7 3700X.



					www.vortez.net
				

















						Review AMD Ryzen 9 3900X, Ryzen 7 3700X y Ryzen 5 3600
					

Llegó el día de uno de los lanzamientos más esperados de esta segunda mitad del año, AMD Matisse o también serie 3000 de AMD o Zen 2, sin duda cualquiera que sea el nombre por el cual sabías de est…




					www.madboxpc.com
				


















						The King is Dead, Long Live the King! – Ryzen 3900X & Ryzen 3700X Review - Bjorn3D.com
					

A New King Has Ryzen! A New King Has Ryzen! The wait for Zen 2 is over and Ryzen 3000 is here! I kno




					bjorn3d.com
				

















						Test - L'Asus Crosshair VIII Formula et Ryzen 3600
					

Nous vous proposons de découvrir nos premières impressions sur le Ryzen 3600 ainsi que sur l'Asus Crosshair VIII Formula.




					vonguru.fr
				











			https://www.guru3d.com/index.php?ct=articles&action=file&id=51783
		
















						AMD Ryzen 9 3900X & Ryzen 7 3700X ‘Zen 2’ CPU Review - KitGuru
					

AMD has launched its Zen 2 architecture in the form of the Ryzen 3000 processors. Slotting directly




					www.kitguru.net
				













			https://lanoc.org/images/reviews/2019/amd_ryzen_gen_3/aida2.png
		













						Zen 2 - AMD Ryzen 7 3700X und Ryzen 9 3900X im Test - Benchmarks bei Standardtakt: AIDA64 - Planet 3DNow!
					

Auf Planet 3DNow! gibt es alle wichtigen Informationen für AMD-User: News, Downloads, Support, Tests



					www.planet3dnow.de
				

















						AMD's Ryzen 7 3700X and Ryzen 9 3900X CPUs reviewed
					

Memory subsystem performance AIDA64’s basic tests of memory bandwidth and latency don’t mean much on their own, but they can give us some insight into why some of our later...




					techreport.com
				














						AMD Ryzen 3900X and 3700X (Zen2) Review
					

It's here, it's finally here -- Zen 2! Check out our review on the AMD Ryzen 3900X and 3700X here!




					www.tweaktown.com


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## biffzinker (Jul 11, 2019)

Metroid said:


> This post will be updated to reflect what I can find. For now these are the aida benchmarks that I found on reviews.
> 
> 
> 
> ...


Wait a sec, some reviews are showing higher copy bandwidth than the i9-9900K?


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## Metroid (Jul 11, 2019)

finished the search, 2 reviews dont have the issue, all the others have the issue.
















						AMD Ryzen 7 3700X Review - Memory Transfer Performance  AIDA64
					

The recipe of 8-cores and 16-threads is well-established in the Ryzen lineup, but now we see it produced in an entirely different way on the brand new 7nm lithographic process. Welcome everyone to the Ryzen 7 3700X.



					www.vortez.net
				
















						Review AMD Ryzen 9 3900X, Ryzen 7 3700X y Ryzen 5 3600
					

Llegó el día de uno de los lanzamientos más esperados de esta segunda mitad del año, AMD Matisse o también serie 3000 de AMD o Zen 2, sin duda cualquiera que sea el nombre por el cual sabías de est…




					www.madboxpc.com
				




And the interesting thing about the last review is that the 3600 in his review dont have the problem too which indicates this might not be the cpu itself, software maybe?


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## Frick (Jul 11, 2019)

Wavetrex said:


> So yea, stop worrying about Zen 2 memory write speed, it's a total non-issue.



Unless you write to RAM a lot, no? I'd imagine @xkm1948 would be interested in this. I don't know enough about RAM to say for sure.


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## HTC (Jul 11, 2019)

Metroid said:


> finished the search, 2 reviews dont have the issue, all the others have the issue.
> 
> 
> 
> ...



Perhaps different versions of AIDA used? If so, which is the correct one?


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## Metroid (Jul 11, 2019)

HTC said:


> Perhaps different versions of AIDA used? If so, which is the correct one?



Even if it was, how the 3900x is unaffected? ehhe, we could say ryzen 3xxx might have some problem, this is so complicated that it could be. It's funny, all reviews pointed that aida memory write issue on 3600 and 3700x and none has any answer what caused that and those people are professionals.

What I'm checking now is if benchmarks differ that much because of that issue. 

Update, benchmarks dont differ that much, still within the margin of error, anyway I give up.


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## Brusfantomet (Jul 11, 2019)

If the memory controller on Ryzen 3000 needs two CCDs for full utilisation of the bandwidth, it will be interesting to see how a possible GPU as the second CCD will perform. If it at least is guaranteed bandwidth for writes.


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## Vario (Jul 11, 2019)

Or is it possible the reviewer was lazy and just reduced core and thread count on a 3900 to simulate a 3700 instead of testing a proper 3700?


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## Metroid (Jul 12, 2019)

Vario said:


> Or is it possible the reviewer was lazy and just reduced core and thread count on a 3900 to simulate a 3700 instead of testing a proper 3700?



Unethical but yeah, it could have been.


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## Metroid (Jul 16, 2019)

in this video here 7:01 minutes 








He says amd had to make a compromise here, so the low memory write issue is actually not an issue, so i guess this discussion is over.


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## HD64G (Jul 30, 2019)

A relative to the RAM & Zen2 topic video:


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## Wavetrex (Jul 30, 2019)

About that fast ram...

Does anyone here thinks it will matter A LOT MORE for the upcoming 3950X than it does for all the other CPUs with less cores?

3900X already shows slightly more difference for faster ram than 3600(X) (they both use 6-core CCD)...
Adding 4 more cores (8 threads) will certainly increase competition for memory access !

I have a good feeling that the fast 3600 CL16 RAM will shine bright for 3950X, and actually be faster than 3200 CL14 (which is not the case for current existing CPUs)
The increased IF bandwidth will also matter more when 8 cores need to exchange data with another 8 cores, than 6+6.
It's also possible that 3950X will boost better by having chiplets of higher quality, so more Mhz will need a tiny bit more RAM performance to work at max capacity.

I guess we'll see in 2 months time or so


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## EarthDog (Jul 30, 2019)

In situations that can use that core/thread count, sure... othewise, in the vast majority of situations, no.


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