DDR4 for Zen 3 build - Mhz vs CAS latency?

Light1984

Limp Gawd
Joined
Dec 31, 2004
Messages
441
I saw a mention of a 4ghz kit with CL15 from gskill. Is that a 2x 8gb kit I assume? I've found two kits, CL16 vs CL17 in the 32gb flavor. Is one going to be better than the other based on secondary timings?

CL16
CL17

Of course neither are on the QVL list for the ROG crosshair hero dark I'm looking at... Need to figure something out for my 5800x build. I'm going to assume the IF is better this time around and 4ghz is the "sweet spot" on memory.
 
Last edited:

thesmokingman

Supreme [H]ardness
Joined
Nov 22, 2008
Messages
6,435
I saw a mention of a 4ghz kit with CL15 from gskill. Is that a 2x 8gb kit I assume? I've found two kits, CL16 vs CL17 in the 32gb flavor. Is one going to be better than the other based on secondary timings?

CL16
CL17

Of course neither are on the QVL list for the ROG crosshair hero dark I'm looking at... Need to figure something out for my 5800x build. I'm going to assume the IF is better this time around and 4ghz is the "sweet spot" on memory.

I think you and a lot of ppl are jumping the gun. First, even if the IMC could handle 2000mhz, it most likely won't run that speed at high densities especially with four sticks populated. I wouldn't buy the ram until I know with some certainty that it will work.
 
Joined
Nov 13, 2006
Messages
2,858
I just went with this gskill Trident Z Neo Series: https://www.amazon.com/gp/product/B07WXML87M/

It's CL16 (16-19-19-39) at 1.35V. I'm fairly confident this RAM will work as it is compatible with Zen 3... and with the voltage pushed a little, odds are it may even do 3800 as well. Even if 4Ghz is the "sweet" spot, I just don't see the performance difference being all that great from a solid 3600 kit that can probably be pushed/OC'ed a little higher. To get a Gskill 4000 kit, you are going to A) Have to find it available first, B) Open your wallet and empty it out to get it and C) Take the risk that it will be compatible and work with the new Zen 3 chip at that speed.

My advice would be to get something that is known to work with Zen 3 if you are going to buy now... or simply wait until the new chip drops in November and you can cherry pick what is confirmed to work then - but odds are high speed memory kits are going to become rather scarce then...
 
Last edited:

Light1984

Limp Gawd
Joined
Dec 31, 2004
Messages
441
I think you and a lot of ppl are jumping the gun. First, even if the IMC could handle 2000mhz, it most likely won't run that speed at high densities especially with four sticks populated. I wouldn't buy the ram until I know with some certainty that it will work.

You may be right, but the kits I linked are two stick kits. Not looking at 4. My thinking is probably somewhat a result of the Ampere fail. I'm trying to get stuff before it goes oos for extended periods in preparation. Both kits a linked are already oos, but I'm hoping will come back soon. If the ryzen 5000 series don't do 2ghz on the IF, then I could just down clock the memory and tighten timings to achieve 3600 CL16, no? Just trying to be proactive and haven't built a new system or looked at parts since 2013.
 

thesmokingman

Supreme [H]ardness
Joined
Nov 22, 2008
Messages
6,435
You may be right, but the kits I linked are two stick kits. Not looking at 4. My thinking is probably somewhat a result of the Ampere fail. I'm trying to get stuff before it goes oos for extended periods in preparation. Both kits a linked are already oos, but I'm hoping will come back soon. If the ryzen 5000 series don't do 2ghz on the IF, then I could just down clock the memory and tighten timings to achieve 3600 CL16, no? Just trying to be proactive and haven't built a new system or looked at parts since 2013.

Hmm, I don't doubt that 2000mhz on the IF is possible, it's just that we don't know how strong it is at speed in relation to the density load. Will it run that at 16gb per stick and how many sticks? For you worst case, you can back it down to 3800mhz.
 

Pocatello

DC Moderator and [H]ard DCOTM x4
Staff member
Joined
Jun 15, 2005
Messages
6,340
How much memory is optimal these days?

16gb seems on the low side. 32gb might be enough. Is 64gb too much?

Does it matter based upon the number of cores? If I purchase a 5950x with 12c/24t ... does it matter how much memory I have?

are there fast memory kits 2x32gb? any recommendations?
 
Joined
Nov 13, 2006
Messages
2,858
How much memory is optimal these days?
Depends on what you are doing - I'd say that most users are "safe" with 16 gigs of RAM for most needs. If you tend to want to push things and run resource intensive games/apps, then 32gb is probably a better sweet spot for you.
16gb seems on the low side. 32gb might be enough. Is 64gb too much?
See above. If you are heavy into imaging/video, then maybe 64gb is a better fit for for you, but for most users, yes, it is probably overkill.
Does it matter based upon the number of cores? If I purchase a 5950x with 12c/24t ... does it matter how much memory I have?
Not really. But I doubt anyone buying a $800 CPU would be gimping out on the amount of RAM they pair it with. Seems silly to go less than 32Gb given the cost/performance being sought.
are there fast memory kits 2x32gb? any recommendations?
Kits tend to be faster with tighter timings when you stick to the lower density end of the spectrum. 32gb sticks tend to not offer the same performance levels that 8gb or 16gb sticks can offer due to this reason. I.E. You will typically find better performing 64gb kits at 4x16gb then with 2x32gb.
 

Epos7

Gawd
Joined
Aug 31, 2015
Messages
634
I paid a pretty penny for G.Skill's F4-3600C16D-32GTZN kit back in April. Now looks like a good time to buy if you can find memory in stock. Guessing demand will shoot up once Zen 3 launches.

I haven't tried overclocking my sticks yet, but they're binned for C14 C16 at 3600 so I'm hopeful they can do C16 C18 at 4000 if that's beneficial for Zen 3.
 
Last edited:

kamikazi

Gawd
Joined
Jan 19, 2006
Messages
746
I paid a pretty penny for G.Skill's F4-3600C16D-32GTZN kit back in April. Now looks like a good time to buy if you can find memory in stock. Guessing demand will shoot up once Zen 3 launches.

I haven't tried overclocking my sticks yet, but they're binned for C14 at 3600 so I'm hopeful they can do C16 at 4000 if that's beneficial for Zen 3.
No way those are spec'd for C14 at 3600. I show C16. Maybe C14 at 3200. Probably C19 at 4000, standard B-Die.
 

RavenX

Limp Gawd
Joined
Oct 27, 2006
Messages
296
Is it true that overclocked ram runs more stable if your system has 2 sticks compared to 4? So if I want 16gigs its better to run 2x8 vs 4x4?
 

Shikami

Gawd
Joined
Apr 5, 2010
Messages
745
The "stability" has more to do with Ryzen's IMC to DIMM banks topology used by the motherboard manufacturer. Topology, VRM's, and then installed DIMMS amounts to banks. Those are the main agitators to stability with frequency being the cherry on top. A search on Ryzen topology will make you smaller. Go ask the internet, what the door knob said.....


Daisy if you 1 DIMM per channel. T if you 2 DIMMs per channel....
 

motqalden

[H]ard|DCOTM x3
Joined
Jun 22, 2009
Messages
1,689
I've been wondering about that myself. I got a pair of Gskil 32gb 3200mhz CAS 16 sticks last week. Wondering If I should go for the 32GB 3600mhz CAS 18 set instead.

The other thing is you can probably get that kit running at 3600 with a bit of tweaking. I have a 3200 cas 14 kit that i am running 3600 cas 15
Ryzen Dram Calculator can be very helpfull to point you in the right direction of the sub timings and voltages you will need.
 

tunatime

Well...OK
Joined
Sep 15, 2011
Messages
4,168

Rizen

[H]F Junkie
Joined
Jul 16, 2000
Messages
9,364
Thanks for the advice. First time I have seen it suggested to avoid Corsair, have used them for years over several builds without issue.
FWIW I have that Vengeance memory kit running at 3800MHz CL16 no problems on my 3900X. I was able to cut memory latency down from mid 70s to 66.3ns through tweaking it.

It's not "as good" as Samsung B-dies but it's also readily available and easy to overclock.
 

Light1984

Limp Gawd
Joined
Dec 31, 2004
Messages
441
Alright friends, I pulled the trigger on this Kit. I couldn't find compatibility on either AMDs qvl or the motherboard qvl from asus, lol. Fingers crossed, LMAO. It's b-die, so worst case I can break even on it I think if I have to sell and get something different. What are your thoughts, dumb to buy this early for 5000 series? I'm worried about supply, but I probably shouldv'e waited. Oh well
 

Rizen

[H]F Junkie
Joined
Jul 16, 2000
Messages
9,364
I'm going to keep the memory I have now (3800MHz CL16) and wait a month or two and see what memory manufacturers release. If Zen 3 really does recommend 4000MHz as the sweet spot I imagine we'll see more competition (and lower prices).
 

mda

[H]ard|Gawd
Joined
Mar 23, 2011
Messages
1,920
Since Zen3 is moving to an 8 core chiplet, I'm guessing RAM will make even less of an impact this time around. AMD has been working hard to decouple RAM speed with actual CPU performance since Zen1
 

pclausen

Gawd
Joined
Jan 30, 2008
Messages
531
^^^ I hope that's true ^^^

I'm planning on running my now 4 year old 2x16 pair of 3200 CL16 with my 5800/5900 (whichever one I can get my hands on first).

tridentz.JPG
 
Joined
Nov 13, 2006
Messages
2,858
^^^ I hope that's true ^^^

I'm planning on running my now 4 year old 2x16 pair of 3200 CL16 with my 5800/5900 (whichever one I can get my hands on first).

View attachment 293364

You should be fine... Take a look at this post and examine the memory and its timings/CAS that was used in that particular benchmark. Unless the whole thing is fake (and I don't see why it would be), it appears that what you have would do even better than this.
 

Astral Abyss

2[H]4U
Joined
Jun 15, 2004
Messages
2,834
Alright friends, I pulled the trigger on this Kit. I couldn't find compatibility on either AMDs qvl or the motherboard qvl from asus, lol. Fingers crossed, LMAO. It's b-die, so worst case I can break even on it I think if I have to sell and get something different. What are your thoughts, dumb to buy this early for 5000 series? I'm worried about supply, but I probably shouldv'e waited. Oh well
I bought the same RAM a week ago. If nothing else, it'll give me something to play around with once Zen 3 arrives. A lot of 4000MHz RAM on Newegg has gone OOS the past 2 weeks, especially the cheaper kits. I was casually keeping an eye on prices and decided it wasn't worth waiting until Zen 3, because besides the OOS items, Newegg has been creeping up the price across the board. It went up $10 on everything rated 4000MHz the day after I bought my kit.
 
Joined
Nov 13, 2006
Messages
2,858
i am also looking at getting some memory soon for a 5950X or 5900X build, i have it narrowed down to 2 kits i think, i have no need for RGB crap so are these kits the same minus RGB ??

Gskill ripjaws
https://www.newegg.com/g-skill-64gb-288-pin-ddr4-sdram/p/N82E16820232916


trident z neo
https://www.newegg.com/g-skill-64gb-288-pin-ddr4-sdram/p/N82E16820232865
Yep, pretty much - they are both G.Skill, are the same capacity/density, and have identical CAS, timings and freq. I bought the Neo version myself. I've never owned RAM that can potentially cause epileptic seizures in a small percentage of the populous, so I figured I'd give them a go.
 

123Lanoix

2[H]4U
Joined
Nov 13, 2005
Messages
4,046
I am starting to look into components for my first new build in over 8 years and am currently stuck on which RAM modules to go with.

I vaguely remember RAM latency being important, but haven't been able to find a quick and easy answer as to whether that is still the case with the latest CPUs and motherboard chipsets.

The toss up is between the Corsair Vengeance RGB PRO 32GB (2x16GB) DDR4 3600 (PC4-28800) C18 and CORSAIR DOMINATOR PLATINUM RGB 32GB (2x16GB) DDR4 3200 (PC4-25600) C16.

https://www.amazon.com.au/CORSAIR-V...rsair+32gb+ddr4+3600mhz&qid=1602390047&sr=8-3

https://www.amazon.com.au/gp/product/B07N3LDKR1/ref=ox_sc_act_title_1?smid=ANEGB3WVEVKZB&psc=1

Does lower latency trump higher mhz?
All you really need is 3600mhz CL16 anything better for day to day stability is pointless. If you want to run it at absolute max which is like 3733mhz FCLK 1900mhz but it puts more stress on the memory controller without much benefit.
 

Starrbuck

2[H]4U
Joined
Jun 12, 2005
Messages
2,666
All you really need is 3600mhz CL16 anything better for day to day stability is pointless. If you want to run it at absolute max which is like 3733mhz FCLK 1900mhz but it puts more stress on the memory controller without much benefit.
I believe 3800 FCLK and 1900MHz Infinity Fabric is the maximum. Not sure if it will be any higher to any benefit on Zen 3 yet.
 

123Lanoix

2[H]4U
Joined
Nov 13, 2005
Messages
4,046
I believe 3800 FCLK and 1900MHz Infinity Fabric is the maximum. Not sure if it will be any higher to any benefit on Zen 3 yet.
It won't it's the same I/O die and memory controller as ZEN 2 so no change in memory support.
 

Starrbuck

2[H]4U
Joined
Jun 12, 2005
Messages
2,666
Honestly I think any of the neo line can do that. My 32kit does one tick under 3800 at c14 with the same 1.5v sadly my imc on my 3960 won't do 1900 no matter what I tried. The key is to get the secondaries right my board had them looser then my ex gf.
My 3200 CL14 kit won't do CL14 any higher than 3333, but it does CL15 up to 3733 stable at 1.46v. My 3700X does 1866 on the infinity fabric well but not 1900 with this kit. However, with the 3800 CL14 kit, it will run 1900 all day at 1.5v. I had to raise other related voltages to get the 3200 kit to 3733 and there was clearly more heat that I had to deal with.
 

MHzTweaker

n00b
Joined
Jul 29, 2009
Messages
39
I just recently upped to 4 sticks of Trident Z Neo 14-14-14-34 (64GB)
I've been a die hard G.Skill buyer for at least 10 years. I've seen more issues with other RAM brands than G.Skill including Corsair and I used to buy Corsair myself.
https://www.newegg.com/g-skill-32gb...820232849?Item=N82E16820232849&quicklink=true

Whenever the 4th gen Threadripper shows up I will be more interested in trying out things like PCIe x4 RAID 0 NVMe drives than overclocking my RAM. I feel this sort of improvement will be more noticeable in real life than a 3200->3600 memory overclock.
 

Attachments

  • Trident Z Neo.jpg
    Trident Z Neo.jpg
    175.7 KB · Views: 0

Dan_D

Extremely [H]
Joined
Feb 9, 2002
Messages
57,226
Honestly I think any of the neo line can do that. My 32kit does one tick under 3800 at c14 with the same 1.5v sadly my imc on my 3960 won't do 1900 no matter what I tried. The key is to get the secondaries right my board had them looser then my ex gf.

Nope. The Hynix DDR4 3600MHz modules will not do that in my experience.
 

ThreeDee

[H]F Junkie
Joined
Sep 5, 2001
Messages
10,991
I have 2 x 16GB Hynix chipped Hyper X Predators that are rated XMP 3200 CAS 16-18-18-18-36 1.35v
I had them running 3800 CAS 18-22-22-22-38 1.41v with fclk 1900 on my 3700x on my ASRock x570 Steel Legend ..w/PBO enabled

but ..

I think with PBO it overvolted my 3700x a bit too much and degraded the chip .. now , the memory can still run the same ..but 1800 is max on fclk (PBO disabled).
So I run memory at 3600 CAS 16-20-20-20-36 1.370v ..also, new 3.30 BIOS AMD AGESA Combo-AM4 V2 1.1.0.0 is garbage for anything other than XMP on memory.

How much memory is optimal these days?

16gb seems on the low side. 32gb might be enough. Is 64gb too much?

I do light video encoding stuff and only play one game and that is Hunt:Showdown .. There was discernible different in game play 'feel" going from 16 to 32gb with same speed memory (before I got into memory tweaking and fclk's ..etc ..just enable XMP profile and go). Maybe one memory had tighter sub timings than the other ..I don't know .. and I don't have any hard numbers to prove anything .. just that the game "felt" noticeably smoother with more RAM.

I should start my own youtube reviewer channel and call it "Game Feelings" .. :woot:
 

Chelica

2[H]4U
Joined
Aug 8, 2003
Messages
2,617
Ouch, I just decided to go with a 3600 32GB kit. Will be selling my 3200 32GB kit soon. I was building an Intel rig until I pivoted and the memory is now outside of the return period...
 

SvenBent

2[H]4U
Joined
Sep 13, 2008
Messages
3,209
It...can. But there are a lot of factors regarding it. I believe, and I may be wrong, that cas 16 DDR4 -3200 performed on par with CAS18 DDR4-3600 in Zen 2.

We won’t know for sure how Zen 3 behaves until someone tests it though.
i belive you are incorrect

3200MHz/CAS16 has the sime real life time latancy in the CAS as 3600MHz/CAS18
So same Latancy for one operation but the later still transfer data faster
plus there are a handfuld of other operation latancies as well to take in.
 

amd7674

[H]ard|Gawd
Joined
Jan 1, 2007
Messages
1,728
a lot of good info here...

7) What is the best memory to buy?

What is the fastest possible RAM you can run with 1:1 fclk?
DDR4-4000. 2000MHz fclk is to the Ryzen 5000 Series what 1900MHz fclk was to the Ryzen 3000 Series. Many samples can do it, but not all. In upcoming AGESAs, we will be implementing additional tuning that will make reaching 2000MHz easier. This is not a guarantee. There is no “safe bet” that your CPU will reach this frequecy. But don’t be surprised to see a bunch of people bringing that magical 2000MHz fclk home with DDR4-4000.
Okay, so what’s the best price/performance?
DDR4-3600 continues to be a “sweet spot.” The kits are inexpensive, widely available, perform well, and have good compatibility. Is it the best in every category? No, but that’s not what the sweet spot is. 3600 is a good bet because it’s a good value in perf/$ for someone who wants to plug and play. Is it the best possible performance? No. Is it close? Yes, and without tinkering.
What’s the best memory, even if i have to overclock?
Probably very tight timing 3600 or 3800, just like the Ryzen 3000 Series. The timings on these memory bins can be super aggressive versus higher memory speed grades, and that usually overpowers frequency.
I only bought 3200, did i do bad?
No, DDR4-3200 is typically binned with tight timings that makes it very competitive with a weak or average DDR4-3600 kit. You’re not missing out on a ton of performance, but there are gains to be had w/ OC if you’re interested in it.
Did you change the memory controller?
No. Everything you know about memory from the Ryzen 3000 Series still applies. Everything. In full. Except the ceiling is now +100MHz higher @ DDR4-4000 for good samples.
 

Revenant_Knight

Limp Gawd
Joined
Nov 18, 2011
Messages
501
i belive you are incorrect

3200MHz/CAS16 has the sime real life time latancy in the CAS as 3600MHz/CAS18
So same Latancy for one operation but the later still transfer data faster
plus there are a handfuld of other operation latancies as well to take in.

Yeah...looks like I was thinking of CAS 14 DDR4-3200 vs CAS 18 DDR-3600.

Thanks for catching that. I've been off my game lately for some reason. I was remembering this video.

 
Top