Friday, May 10th 2019

AMD Ryzen 3000 "Zen 2" a Memory OC Beast, DDR4-5000 Possible

AMD's 3rd generation Ryzen (3000-series) processors will overcome a vast number of memory limitations faced by older Ryzen chips. With Zen 2, the company decided to separate the memory controller from the CPU cores into a separate chip, called "IO die". Our resident Ryzen memory guru Yuri "1usmus" Bubliy, author of DRAM Calculator for Ryzen, found technical info that confirms just how much progress AMD has been making.

The third generation Ryzen processors will be able to match their Intel counterparts when it comes to memory overclocking. In the Zen 2 BIOS, the memory frequency options go all the way up to "DDR4-5000", which is a huge increase over the first Ryzens. The DRAM clock is still linked to the Infinity Fabric (IF) clock domain, which means at DDR4-5000, Infinity Fabric would tick at 5000 MHz DDR, too. Since that rate is out of reach for IF, AMD has decided to add a new 1/2 divider mode for their on-chip bus. When enabled, it will run Infinity Fabric at half the DRAM actual clock (eg: 1250 MHz for DDR4-5000).

This could turn into an additional selling point for AMD X570 chipset motherboards, as they'll have a memory frequency headroom advantage over boards based on older chipsets as their BIOS will include not just the increased memory clock limit, but also the divider mode. Of course this doesn't mean that you can just magically overclock any memory kit to these 5 GHz speeds - it's probable that only the best of the best modules will be able to get close to these speeds.

1usmus also discovered that the platform adds a SoC OC mode and VDDG voltage control. We've heard from several sources that AMD invested heavily in improving memory compatibility, especially in the wake of Samsung discontinuing its B-die DRAM chips.
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102 Comments on AMD Ryzen 3000 "Zen 2" a Memory OC Beast, DDR4-5000 Possible

#1
bonehead123
Nice, IF it works as expected, and if it does, could we therefore look forward to having DDR-7@10k speeds in a few years for example ???
The DRAM clock is still linked to Infinity Fabric (IF) clock domain
So if this is the case, why not just replace the IF with optical or another more advanced interlink method ??
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#3
MikeMurphy
Maybe memory bandwidth is important because they supposedly need to feed 16 cores and 32 threads on a dual 64-bit memory channel architecture.

bonehead123 said:

Nice, IF it works as expected, and if it does, could we therefore look forward to having DDR-7@10k speeds in a few years for example ???

So if this is the case, why not just replace the IF with optical or another more advanced interlink method ??
Integrated HBM, my dude.
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#4
GoldenX
And I was happy with a 3333MHz overclock on my 2400MHz RAM...
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#5
RH92
Very nice , honestly personally im much more hyped about better memory support/OC on Zen 2 than higher core count or/and clocks ! Hopefully the difference between X570 and older chipsets won't be that big otherwise it would ruin the experience .
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#6
londiste
Wouldn't the 1/2 divider pose a small problem with decreasing IF clock when it gets enabled?
Assuming without divider memory goes to 3600 (roughly how it is now), going from 3600 to 4000 and enabling the divider to facilitate these speeds would mean IF clock going from 1800 to 1000, right?

IMC is in the CPU, so divider support in BIOS could theoretically be available for older boards as well.
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#7
Bones
I do know one thing, I'll have a Ryzen 3 on my short list of hardware to buy at that time.
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#8
Manu_PT
Rocking my 4000mhz CL18 on Z390, you will see how good it is when ram is clocked high :)
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#10
danbert2000
londiste said:

Wouldn't the 1/2 divider pose a small problem with decreasing IF clock when it gets enabled?
Assuming without divider memory goes to 3600 (roughly how it is now), going from 3600 to 4000 and enabling the divider to facilitate these speeds would mean IF clock going from 1800 to 1000, right?
That's how I understood it, IF speeds will decrease compared to 3200 MHz DDR4 speeds. Which begs the question, why would you push for higher memory clocks if it's going to wind up slowing your processor down? I think that the better memory compatibility will be the big gain, and only overclockers chasing the highest speeds for fun will actually find this useful.
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#11
Hugh Mungus
I wouldn't use 1/2 mode as a) I can't be bothered with that kind of ram speed and b) I'll probably get the same performance with full IF and slower RAM, like 3200 or maybe 3600MHz if I upgrade my RAM!
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#12
EntropyZ
Everything I keep reading from the start of the Ryzen 3000 "leaks" just seems to good to be true now, I'm not gonna lie. If it is, well, it probably is. I was already hyped to hear there's a bump in IPC, but this is too much IMO. It just makes me think of the aftermath when the thing actually launches.

Regardless, they should be a decent upgrade from a 1000 series chip, at least for gaming.

Maybe it is an earnest effort to improve on the uArch. All I can do is wait and watch. (And stay out of any incoming drama)
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#13
NdMk2o1o
So it has support in the bios for DDR4 5000, doesn't mean anything, my Asrock Ab350m has support for DDR4 4000, it still doesn't get anywhere close to that the same as all other current gen and 1st gen Ryzen boards and processors. That said if Ryzen 2 can hit 4000mhz DDR4 with 4.5+Ghz chiplets available then that is more than enough for my and many other peoples needs. The interesting this is the seperate I/O chip that replaces the on die memory controller, maybe they have overcome many of the limitations of Ryzen and Ryzen+ memory issues.
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#14
bug
NdMk2o1o said:

So it has support in the bios for DDR4 5000, doesn't mean anything, my Asrock Ab350m has support for DDR4 4000, it still doesn't get anywhere close to that the same as all other current gen and 1st gen Ryzen boards and processors. That said if Ryzen 2 can hit 4000mhz DDR4 with 4.5+Ghz chiplets available then that is more than enough for my and many other peoples needs. The interesting this is the seperate I/O chip that replaces the on die memory controller, maybe they have overcome many of the limitations of Ryzen and Ryzen+ memory issues.
Pretty much what I was thinking, but still, wow!

Zen's memory "issues" come down to AMD having to draw the line somewhere and come up with a finished product. When they did that, a lot of tweaking for the memory controller got thrown under the bus (read: postponed to Zen2). The I/O chip has nothing to do with that. That was moved to a separate chip because AMD concluded the memory controller doesn't scale and so it will continue to be built on 14nm.
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#15
1usmus
AMD Memory Guru
NdMk2o1o said:

So it has support in the bios for DDR4 5000, doesn't mean anything, my Asrock Ab350m has support for DDR4 4000, it still doesn't get anywhere close to that the same as all other current gen and 1st gen Ryzen boards and processors. That said if Ryzen 2 can hit 4000mhz DDR4 with 4.5+Ghz chiplets available then that is more than enough for my and many other peoples needs. The interesting this is the seperate I/O chip that replaces the on die memory controller, maybe they have overcome many of the limitations of Ryzen and Ryzen+ memory issues.
in my case, what is stated is reality (4000 on 2700x)

There are a lot of improvements in X 570, MSI and ASUS are preparing legendary tops ;)

Posted on Reply
#16
NdMk2o1o
bug said:

Zen's memory "issues" come down to AMD having to draw the line somewhere and come up with a finished product. When they did that, a lot of tweaking for the memory controller got thrown under the bus (read: postponed to Zen2).
Wow, it's great to have some real inside knowledge on building the Zen architecture and that even though Ryzen+ was released a whole 12 months later (probably in development for 3+ years as with the 1st gen which probably would of been more like 5 years) Now I know they just rushed it out the door with that darn memory controller being thrown in at the last minute. Btw how did it feel to be working with Jim Keller on a daily basis? :p

1usmus said:

in my case, what is stated is reality (4000 on 2700x)

There are a lot of improvements in X 570, MSI and ASUS are preparing legendary tops ;)


Yes you're the exception to the rule when you consider most people, sure some can/have reached that speed the majority top out at 3400-3600. Even 4000 acheivable on most x570 boards would be acceptable, obviously if higher is more common rather than being an exception to the rule that's just swell, though in all likelyhood it wouldn't bother me anyway as I'd rather spend £150 on decent ram that will hit 4000 than double that for 16GB that in the best of the best boards and circumstances hit 5000

Edit: btw big thanks for all the time you have dedicated to Ryzen RAM calculator, it didn't seem to work out for me the last time I used it though I notice you have since released a newer version and I may download that again now and try and shoot for 3400+ on my RAM which I've not been able to acheive as of now.
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#17
lsevald
So what memory should we get for Ryzen 3000? For budget, mid range and high end? If it's possible to predict this early. Just worried I will regret not buying a samsung B-die based kit now, before they are all gone...
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#18
GoldenX
It's a new MC, wait and see.
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#19
phanbuey
i hope they fix the issue with filling all the ranks...

What point is a 16/32 core proc where you are capped at 16GB dual channel if you want to run high speed dimms.
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#20
eidairaman1
The Exiled Airman
1usmus said:

in my case, what is stated is reality (4000 on 2700x)

There are a lot of improvements in X 570, MSI and ASUS are preparing legendary tops ;)

[ATTACH alt="PIC 5.jpg"]122641[/ATTACH]
So a Crosshair VIII Extreme and Asrock a Taichi X570 Ultimate?
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#22
bug
NdMk2o1o said:

Wow, it's great to have some real inside knowledge on building the Zen architecture and that even though Ryzen+ was released a whole 12 months later (probably in development for 3+ years as with the 1st gen which probably would of been more like 5 years) Now I know they just rushed it out the door with that darn memory controller being thrown in at the last minute. Btw how did it feel to be working with Jim Keller on a daily basis? :p
Well, this isn't inside knowledge, AMD publicly stated it. And the memory controller wasn't rushed, they just didn't have the luxury to tweak it as much as they (knew they) could.
Posted on Reply
#23
NdMk2o1o
bug said:

Well, this isn't inside knowledge, AMD publicly stated it. And the memory controller wasn't rushed, they just didn't have the luxury to tweak it as much as they (knew they) could.
Where's the quote for this?
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#24
Mamya3084
Hopefully it can achieve at least 3200 with 4 sticks. My 1800x can only achieve 3000mhz with 4x 3466 gskill b-die memory kit.
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#25
JAB Creations
Being able to overclock the RAM with all four dimms is important to me. I doubt I'll have 5GHz RAM though as things improve for me I'd love to benchmark the RAM differences and release the information myself about how much it's worth buying faster clocked RAM plus the difference between two and four dimms. I'm very grateful that they took the time to really iron out the issues that have been mentioned and it's my hope that the 3000 series Ryzen Two generation will be as rock solid as possible.
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