Note about Memory Configurations with Zen3 - 4 RAM sticks seemingly better than 2

G

Gavras

Master Poster
Below content is from the original poster. Highlighted and edited by @Scott for new customer consideration. Very much worth a watch to see if if can affect your potential memory choices for any Zen 3 builds.



I use the word interesting with caveats lol.

the review looks at 2x sticks vs 4 x sticks.

for the Zen 3’s this shows some decent differences.

it also shows how bench mark reviews can be misleading depending on memory configurations.


it also shows difference between 3200 v 3600


I guess it’s not how much you have, but how’s it’s used.


I think over next 6 months, we will see more reviews showing just what Zen 3 does, especially with latest AMD gfx cards.
 
Last edited by a moderator:
Scott

Scott

Behold The Ford Mondeo
Moderator
Now that's a really fantastic finding and I'm now going to have to re-visit all my recommendations for high end builds..... thanks for that :ROFLMAO: :ROFLMAO: :ROFLMAO:

This is a VERY unique difference. I've seen it in the past where there have been outliers that make good use of 4 sticks over 2, but over the piece it's been detrimental. This is actually a really fantastic design as everything is clearly working in harmony with the AMD architecture. Using 4 sticks was previously a burden, where now it is an advantage!

I'm thinking this should probably be a sticky for a while.

Do you mind if I edit your thread a little and sticky it?
 
G

Gavras

Master Poster
Scott said:
Now that's a really fantastic finding and I'm now going to have to re-visit all my recommendations for high end builds..... thanks for that :ROFLMAO: :ROFLMAO: :ROFLMAO:

This is a VERY unique difference. I've seen it in the past where there have been outliers that make good use of 4 sticks over 2, but over the piece it's been detrimental. This is actually a really fantastic design as everything is clearly working in harmony with the AMD architecture. Using 4 sticks was previously a burden, where now it is an advantage!

I'm thinking this should probably be a sticky for a while.

Do you mind if I edit your thread a little and sticky it?
Click to expand...
Feel free, it’s what the internet is for, sharing information.
 
Scott

Scott

Behold The Ford Mondeo
Moderator
Just thought of a serious upside. My current RAM can move to a new system with 2x8GB in it for a performance bump :ROFLMAO:
 
AccidentalDenz

AccidentalDenz

Lord of Steam
Back to the configurator I go. I had put 2x16Gb 3200Mhz in my order initially, switched to 2x8Gb 3600Mhz when I changed the CPU to the 5900X as I'm not convinced I'll get around to Flight Simulator, although I do have the budget for more RAM. May be switching to some kind of 4x configuration, but no idea which yet... 🤔
 
Scott

Scott

Behold The Ford Mondeo
Moderator
Keep in mind that it's more to do with 1080p gaming where the CPU is the limitation, rather than the GPU, but still.... it's worth keeping in mind.

If occupying the 4 slots I would recommend going for a 32GB total. That way you won't have any buyers remorse and have to replace all the RAM should you want to up from 16 to 32 at a future date.
 
M

Mask3d

Silver Level Poster
Found this on Reddit:

Credit to U/Zero_exe_exe

The reason for this is that he's using 4 sticks of single rank, vs 2 sticks of single rank. When using 4 ranks, it allows the memory cycle to start before finishing a previous cycle. It's been talked about here on Reddit before that dual rank outperforms single rank at the same frequencies and Cas Latency.

One thing to consider, is the topology of the mother board. Most X570 and X470 boards are Daisy Chain. Because A2 and B2 are jumping off A1 and B1 respectively in this setup, 4 sticks can create stability headaches and impact overclocking. You WILL still see a performance uplift on daisy chain when using 4 sticks single rank, however it is a more suitable topology for dual rank at the same speeds.
In T-Toplogy boards, the traces split and go to all 4 slots evenly making it ideal for running 4 sticks single rank for stability and overclocking.

So summary: Do your research on your motherboard.
Daisy Chain? Run two sticks Dual Rank.
T-Topology? Run four sticks Single Rank.

**EDIT:**Find your motherboard on this spreadsheet, the topology is listed
https://docs.google.com/spreadsheet...FnsZYZiW1pfiDZnKCjaXyzd1o/edit#gid=2112472504
Click to expand...

One thing I note is that there are no 2x16GB options for 3600mhz in the PCS configurator so I'm still happy enough with my choice.
 
btmi

btmi

Member
Having originally started with 4x8GB 3600mhz, then jumped to 2x16GB 3200mhz RGB, I'm having a laugh with this!

My understanding, though, is that the main advantage is having 4 channels vs 2. And from what I can tell, the RGB 2x16gb kit is dual channel ram, meaning you would still have 4 channels. So it still seems to be a bit of a ? to me whether or not 4x8GB will truly be a major improvement, as it would mean giving up the 2 slots for an upgrade path (and the RGB :ROFLMAO:)
 
Scott

Scott

Behold The Ford Mondeo
Moderator
Try not to confuse channels. All standard desktop boards are 2 channel. 4 slots doesn't mean 4 channels. One channel is split across the 2 slots. You are normally into HEDT before hitting 4 channels (although there are 3 channel systems that just confuse matters).

Conventionally, it's best to only use one channel (2 slots) as that means that the memory controller doesn't need to switch between the channels.

When cpu-memory, and vice versa, intensive operations are considered the new AMD chips offer an advantage using both channels. I'm not sure how it's managing this and how it's different from previous hardware, but it's there for all to see in the benchmarks.

For gaming it won't make any odds past 1080p, save for possibly FS2020 where it's the CPU/Memory that mostly bottlenecks performance.

If I go down the AMD 5000 route I'll definitely be opting for 4x8GB.
 
Derngek

Derngek

Silver Level Poster
SpyderTracks said:
Some more in depth tests coming through, I know Gamers Nexus will be releasing one today or tomorrow too:

Click to expand...
I assume that 3600mhz rams will be stable running games on? When I spoke to one of the sales team on the phone a couple weeks ago they reccomended me to go for 3200mhz over the 3600mhz version if it's for gaming
 
btmi

btmi

Member
Scott said:
Try not to confuse channels. All standard desktop boards are 2 channel. 4 slots doesn't mean 4 channels. One channel is split across the 2 slots. You are normally into HEDT before hitting 4 channels (although there are 3 channel systems that just confuse matters).

Conventionally, it's best to only use one channel (2 slots) as that means that the memory controller doesn't need to switch between the channels.

When cpu-memory, and vice versa, intensive operations are considered the new AMD chips offer an advantage using both channels. I'm not sure how it's managing this and how it's different from previous hardware, but it's there for all to see in the benchmarks.

For gaming it won't make any odds past 1080p, save for possibly FS2020 where it's the CPU/Memory that mostly bottlenecks performance.

If I go down the AMD 5000 route I'll definitely be opting for 4x8GB.
Click to expand...

sorry i meant dual RANK. if i understand correctly 2x dual-ranked 16GB dimms provides the same advantage as 4x single ranked 8GB dimms
 
N

Nivek

Silver Level Poster
This has been an interesting read as I have ordered a PC with a Ryzen 5900X and 16GB (2 x 8GB, single rank) 3600MHz RAM. I'm wondering now whether I should upgrade to the 32GB (2 x 16GB, dual rank) 3200MHz RAM (the RGB is a small bonus I must admit :LOL:), or the 32GB (4 x 8GB, single rank) 3600MHz RAM.
I realise it won't make much of a difference either way but would still like to get to most optimal build as we're not talking about a lot of money.
 
Scott

Scott

Behold The Ford Mondeo
Moderator
The most optimal is going for the fastest RAM really. With everything equal, 4 modules is showing to be better than 2. Single rank in theory should be quicker, but it depends on the process. The video listed is very confusing as they have implemented so many variables it's really difficult to track what is best for each scenario. I will be curious to see what Gamers Nexus come out with as their videos tend to be explained more coherently.

I don't think there will actually be any noticeable real world differences but always best to go with what is optimal with the choices offered.

Ironically, I think the best bet is 4x8GB single rank 3600mhz CL16..... unfortunately PCS don't supply this at the moment.
 
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