DDR4 for Zen 3 build - Mhz vs CAS latency?

vjhawk

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Linus had an interesting stream where he discussed the discrepancy in performance numbers between reviewers. And he noted that the common denominator seems to be that the reviewers with lower performance scores for AMD were running only 3200mhz memory. Meanwhile LTT benchmarks used 3600mhz as the standard and concluded that the 5000 series is WAY better than Intel's best. So if you want top end performance out of the 5000 series you really should be using 3600mhz RAM as a minimum. Especially if you crave that 5-6% extra performance that actually has Zen3 beating out Intel's best chip in games and benchmarks.

Silly reviewers, 3200mhz favors Intel. When you have a Ferrari like a 5000x chip, you gotta let it breath with the fastest memory modules!! ;-)
 

Kage-shi

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3800 CL14 is the max you want to go for. That's the best performance with a 1900mhz Infinity Clock. The max Infinity Clock frequency didn't change from 1900mhz according to Buildzoid. Anything above that still crashes. A recent vid from him showed some voltage changes you can make to guarantee 1900mhz too. It used to be not everyone could hit 1900mhz Infinity, so they chalked it up to poor silicon quality. Turns out many of them just didn't know the right voltage tweaks to make. I opted for a really high binned 3600mhz CL14 4x8GB setup that I can OC to 3800mhz and tighten the timings on if I desire. Or if my mobo gives me trouble with the fully populated DIMMs, I can always fall back on the XMP 3600 CL14.
 

vjhawk

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I just watched an interesting video by Steve from Gamer Nexus. Apparently running 4 sticks of DDR4 on the 5600X increases FPS by up to 10%.


That's a crazy performance boost just from going to 2 sticks of ram to 4! I am going to assume this scales for the other CPUs in the 5000 series as well!
 

Light1984

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I just watched an interesting video by Steve from Gamer Nexus. Apparently running 4 sticks of DDR4 on the 5600X increases FPS by up to 10%.


That's a crazy performance boost just from going to 2 sticks of ram to 4! I am going to assume this scales for the other CPUs in the 5000 series as well!

I watched this too and regretted ordering 2x16gb of samsung b die at first. Then I read through some of the comments on the video. Apparently it's not 2 sticks or 4 sticks, it's whether you have 2 rank or 4 rank. The ideal scenario, as it were, is to have 4 ranks. This can be achieved with two sticks of dual rank or four sticks of single rank. So I would be good with the 4000 CL17 kit I got. More info coming next week from GN. They commented on this in the top post on the video as well for clarification to come.
 

D-EJ915

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I watched this too and regretted ordering 2x16gb of samsung b die at first. Then I read through some of the comments on the video. Apparently it's not 2 sticks or 4 sticks, it's whether you have 2 rank or 4 rank. The ideal scenario, as it were, is to have 4 ranks. This can be achieved with two sticks of dual rank or four sticks of single rank. So I would be good with the 4000 CL17 kit I got. More info coming next week from GN. They commented on this in the top post on the video as well for clarification to come.
2x16 bdie is still going to be great, don't worry about it.
 

thesmokingman

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I dunno why the tech jesus video is so popular. It's nothing new. 4 ranks, you get there anyway ya want 4 singles or 2 doubles.
 

Endgame

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Am I the only one that hates this shift from text information where you can get the results in 10 seconds to having to watch a video?

edit
I don’t have 20 minutes to watch this guy ramble. What’s the take away besides 4 ranks of memory? DDR 3200 and ultra tight timings or DDR 4000 with worse timings?
 
Last edited:

Nightfire

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Awesome video...

I agree with Steve here as the other Steve got a little carried away. A few caveats to his test:

1. You need to run a 3080 at low res/settings to get any benifits.

2. It is harder to get a super low latency with dual rank (either double sided dimm or 2 dimms) versus single rank which usually off sets any gains in the first place.

2x8 GB at 3200+ mhz at cas 14 will give you 100% performance in 98% of situations.
 

polonyc2

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I bought a G.Skill 2 x 16GB DDR4 3600 CL 16 Samsung B-Die kit a few weeks back in preparation for my Zen 3 build...looks like I made the right call (a bit more expensive but worth it)...seems like 3600 is still the sweet spot even though there were some rumors of 4000 being the new sweet spot with Zen 3

I'm assuming my 2 x 16GB sticks are dual rank?
 

Nightfire

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I bought a G.Skill 2 x 16GB DDR4 3600 CL 16 Samsung B-Die kit a few weeks back in preparation for my Zen 3 build...looks like I made the right call (a bit more expensive but worth it)...seems like 3600 is still the sweet spot even though there were some rumors of 4000 being the new sweet spot with Zen 3

I'm assuming my 2 x 16GB sticks are dual rank?

From what reviews I've seen, Zen 3 still struggles to do 1:1 above 1900 mhz. The ill-fated Renoir chips, however, could do 2200 mhz with ease.
 

Astral Abyss

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I bought some 16x2 G.Skill CAS 17 4000 in anticipation, but I still have my trusty 4x8 G.Skill CAS 14 3200 single ranks if need be. Supposed to get delivery of my 5950x tomorrow.
 
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G.Skill just released some "new" b die
https://www.gskill.com/product/165/326/1604306130/F4-3600C14D-32GTZN
Trident Z Neo
DDR4-3600MHz CL14-15-15-35 1.45V
32GB (2x16GB) dual ranked
https://www.newegg.com/g-skill-32gb-288-pin-ddr4-sdram/p/N82E16820374093?Item=N82E16820374093

Probably cheaper to get the 3200mhz CL14 b-die kits that are ~$200 but if you want the fancy LEDs and guaranteed overclock...
Thanks for the head's up. I went ahead and ordered a set. I already have a Trident Neo 3600Mhz CL16-19-19-19-39 1.35v kit in hand for a new AMD 5000 based rig I am building next month. This kit is currently back-ordered on the Egg, but figure it should ship by December. I have a feeling it is going to be much more capable and a better performer.
 

irev210

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Thanks for the head's up. I went ahead and ordered a set. I already have a Trident Neo 3600Mhz CL16-19-19-19-39 1.35v kit in hand for a new AMD 5000 based rig I am building next month. This kit is currently back-ordered on the Egg, but figure it should ship by December. I have a feeling it is going to be much more capable and a better performer.
They also have the ripjaws in stock; same specs, no LED, lower price
https://www.newegg.com/g-skill-32gb...820374090?Item=N82E16820374090&quicklink=true
 

Magma

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That looks like it's 256GB (8x32GB) to me, so I'm not even sure what motherboard would have eight slots to use all of those DIMMs.
 

thesmokingman

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That looks like it's 256GB (8x32GB) to me, so I'm not even sure what motherboard would have eight slots to use all of those DIMMs.

Oh yea. Let me have some more coffee, my eyes are missing stuff.

On topic, yea no amd mainstream board.
 
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sram

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Yea, no. First its 256gb, you'll have a hard enough time getting it to run let alone overclock.
Ohh, wait ! Can you please expand? Why do we have 256GB then? How come I can't even RUN it?

The ASUS ROG Zenith II Extreme has 8 slots for example, and it can take a maximum RAM of 256GB if I remember correctly.

https://rog.asus.com/motherboards/rog-zenith/rog-zenith-ii-extreme-model/helpdesk_qvl_memory/

The kit isn't in the QVL though. Similar kits but with CAS of 16 is in the QVL however.

If not 256 GB, I can go for 128GB instead. How about this:

https://www.newegg.com/g-skill-128gb-288-pin-ddr4-sdram/p/N82E16820374089?Item=N82E16820374089

Can I overclock it?? Please bear with me.

Anyway, it seems like I need to do some reading when it comes to RAM speed, overclocking, and selection.
 

thesmokingman

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Ohh, wait ! Can you please expand? Why do we have 256GB then? How come I can't even RUN it?

The ASUS ROG Zenith II Extreme has 8 slots for example, and it can take a maximum RAM of 256GB if I remember correctly.

https://rog.asus.com/motherboards/rog-zenith/rog-zenith-ii-extreme-model/helpdesk_qvl_memory/

The kit isn't in the QVL though. Similar kits but with CAS of 16 is in the QVL however.

If not 256 GB, I can go for 128GB instead. How about this:

https://www.newegg.com/g-skill-128gb-288-pin-ddr4-sdram/p/N82E16820374089?Item=N82E16820374089

Can I overclock it?? Please bear with me.

Anyway, it seems like I need to do some reading when it comes to RAM speed, overclocking, and selection.

Dude, look at the timings. That is not a priority with the kits you chose, cost is.
 

lopoetve

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Ohh, wait ! Can you please expand? Why do we have 256GB then? How come I can't even RUN it?

The ASUS ROG Zenith II Extreme has 8 slots for example, and it can take a maximum RAM of 256GB if I remember correctly.

https://rog.asus.com/motherboards/rog-zenith/rog-zenith-ii-extreme-model/helpdesk_qvl_memory/

The kit isn't in the QVL though. Similar kits but with CAS of 16 is in the QVL however.

If not 256 GB, I can go for 128GB instead. How about this:

https://www.newegg.com/g-skill-128gb-288-pin-ddr4-sdram/p/N82E16820374089?Item=N82E16820374089

Can I overclock it?? Please bear with me.

Anyway, it seems like I need to do some reading when it comes to RAM speed, overclocking, and selection.
Threadripper is limited to 128GB, I believe.

Don't know on TR Pro, but might also be for a high-end EPYC build without ECC?
 

sram

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Dude, look at the timings. That is not a priority with the kits you chose, cost is.
I don't really care about cost for my next possible build. It is not a priority for me. I just want to get what will give me max performance. Sorry I didn't indicate that I'm planning for a Threadripper build (Probably a 3970x or wait for one of the new zen 3 threadrippers). I still don't understand why I can't run 256GB of RAM (similar to the kit I linked) for threadrippers like you said. Is it the tighter timings?

and is it different with the 3990x because I can see that there is a separate QVL list for 64-core Ryzen Threadrippers in the ASUS mobo page:

https://rog.asus.com/motherboards/rog-zenith/rog-zenith-ii-extreme-model/helpdesk_qvl_memory/
 

thesmokingman

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I don't really care about cost for my next possible build. It is not a priority for me. I just want to get what will give me max performance. Sorry I didn't indicate that I'm planning for a Threadripper build (Probably a 3970x or wait for one of the new zen 3 threadrippers). I still don't understand why I can't run 256GB of RAM (similar to the kit I linked) for threadrippers like you said. Is it the tighter timings?

and is it different with the 3990x because I can see that there is a separate QVL list for 64-core Ryzen Threadrippers in the ASUS mobo page:

https://rog.asus.com/motherboards/rog-zenith/rog-zenith-ii-extreme-model/helpdesk_qvl_memory/

You really need to research more. The platform is only validated to 2667mhz at when all 8 channels are populated. The ram you chose has crap timings meaning it is not meant for overclocking. Not sure how many times I gotta repeat that. You wanna overclock yet you pick 256gb ram. You need to wake up, choose your priorities, you cannot have everything.
 

sram

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You really need to research more. The platform is only validated to 2667mhz at when all 8 channels are populated. The ram you chose has crap timings meaning it is not meant for overclocking. Not sure how many times I gotta repeat that. You wanna overclock yet you pick 256gb ram. You need to wake up, choose your priorities, you cannot have everything.
Well, I already said myself that I need to read. But you actually saved me time, you just said it in a way I can understand which I was looking for. It is a compromise or a trade-off. It becomes harder to overclock RAM as you increase the capacity. So if you want capacity, agree to lose overclock-ability. Also, the more slots you populate, the less speed. In fact, and to be more precise, it is not that I want to overclock! It is just I knew from somewhere that 3600 MHz is the RAM speed that goes with threadrippers, so I just wanted to get that kit --which was 3200MHz-- to the standard speed. But since it is actually 2667 MHz which is lower that the kit rated speed, there is no need to overclock. It should actually be run at less than its rated maximum speed. This website here explains it in a good way:

https://www.kitguru.net/components/cpu/luke-hill/amd-ryzen-threadripper-3960x-3970x-cpu-review/

>>>
"Support for quad-channel memory with up to 256GB capacity is provided due to the 32GB capacity limitation of currently available DIMMs in an eight-slot board. ECC support is available, but this is down to the motherboard vendor to implement. In terms of frequency, the situation is slightly complex. Fundamentally, memory support is the same as with Ryzen 3000 as this is still using the Zen 2 memory controller. However, there are more DIMMs to power and manage for Threadripper’s quad-channel configuration.


For 4-DIMM configurations, whether they’re single rank or dual rank, you get official support for 3200MHz. So, 4x8GB, 4x16GB, and 4x32GB will run at 3200MHz. 8x8GB is officially supported at 2933MHz, 8x16GB at 2667MHz, and 8x32GB at 2667MHz. With that said, motherboard support for speeds of DDR4-3600MHz and above will be widespread, as we have seen with Ryzen 3000.


As is the case with Zen 2 Ryzen 3000, passing DDR4-3600MHz memory speeds will trigger a 2:1 divider between the memory clock and the memory controller clock, which imparts a latency penalty. It is best to either manually overclock or lock the memory controller clock if you’re using higher-than-3600MHz DDR4. DDR4-3600MHz C16 is still a good sweet spot according to AMD, and we still like and continue to use DDR4-3200MHz C14"

>>>

I don't need to wake up. I just need to learn something new I didn't know before, which just happened. Excuse my ignorance. You got to ask when you don't know.

Thanks.
 

thesmokingman

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I'll add that at 8x16gb dram speeds topped out at 3400mhz on my 3970x. And it seems others have hit similar limits. When taken in context the threadripper 3k IMC is incredibly good in that regard. However at twice the density, I'd imagine that it will be a bit lower as the load is insane.
 

Lepardi

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I just hate it how manufacturers can hide DR or SR info. It's an essential piece of information that matters more than MHz or CL.
 

Endgame

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I just hate it how manufacturers can hide DR or SR info. It's an essential piece of information that matters more than MHz or CL.
After a certain point it’s almost certainly dual rank (ex, 16GB dimms or larger). 8GB though...
 

spaceman

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Corsair vengeance 2x16 gb 3200 is $114 at best buy now. I have a 5600 cpu. Would that and a 550 tomahawk be a good budget buy?
 

thesmokingman

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lmao!!! I just booted a 5800x with fabric at 2000mhz with soc on auto voltage. The ram is running with slow timings so I can get a baseline. I'm getting a crap ton of whea errors though on stock soc voltage so keep that in mind.
 

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