Question DDR3200 vs 3600 question - just paying for ability to RMA if it doesn't OC?

[PrinceXizor]

So, it's been awhile since I've worried about RAM (last purchase was DDR3 1600). It's clear Ryzen benefits from low latency and higher clock speed RAM, thus the emphasis on sticks that are CL16 and 3600Mhz. So my question, is there any physical difference between 3200 chips and 3600 chips or are we paying for presorting/binning/the ability to RMA a stick that doesn't meet advertised speeds?

 

[MalVeauX]

Heya,

The physical b-die can be different (micron, samsung, etc) and the bin quality is going to likely be variable and different. It's common to get higher stable rated speed RAM and then under-clock it to get tighter timings (such as 4000Mhz RAM that is CL18 and then take it down to 3600Mhz and a lower CL like 16~17, etc depending on the memory); using the RAM tool software to sort out timings. If your goal is over-under clocking it will also matter what motherboard you're using. If you just want plug & play, the 3200Mhz speed is what is official supported by the Ryzen series into Zen 3. So the infinity fabric will operate at 1600 and the RAM will operate at 3200, for the 1:1. If you go to 3600 RAM, then the infinity fabric goes to 1800 to maintain 1:1. It seems so far that latency is the bigger deal though. The speed differences from 3200 to 3600 doesn't seem to be super important compared to timing and latency. It also matters what topology your memory handling is on the motherboard (t-topology vs daisy chain). And it matters if you're using single rank, double rank, etc.

So get 3600Mhz CL16 DDR4 and you can't go wrong.
Or, get 3200Mhz CL14~CL16 DDR4 and you still cannot go wrong.

Consider a lot of the info is pre-Zen2/3 and that RAM was below 3000Mhz back then. Today's RAM is commonly available at 3200Mhz and 3600Mhz without any tweaks needed from you. Just insert, click XMP, and go.

Very best,

 

[PrinceXizor]

Hmm...don't know much about the latter half of what you mentioned, i.e. how AMD's infinity fabric works or the memory topology of my motherboard.
Going to be using ASRock B550M Pro4. I don't OC if it takes anything more than a simple setting tweak. I OC'd the 2500K I think when it was a matter of switching the multiplier to changes the FSB. That's about it for my OC life! I can hunt for the best timings, that's a little easier to parse the myriad of RAM options available. I plan on running 2 x16GB and then adding 2 more sticks in the future and/or swapping out for 2 x 32GB. I understand to run 4 sticks you need looser timings, is that correct? If I run looser timings that means I'm slightly slower too, yes?

 

[Fanatical Meat]

Hmm...don't know much about the latter half of what you mentioned, i.e. how AMD's infinity fabric works or the memory topology of my motherboard.
Going to be using ASRock B550M Pro4. I don't OC if it takes anything more than a simple setting tweak. I OC'd the 2500K I think when it was a matter of switching the multiplier to changes the FSB. That's about it for my OC life! I can hunt for the best timings, that's a little easier to parse the myriad of RAM options available. I plan on running 2 x16GB and then adding 2 more sticks in the future and/or swapping out for 2 x 32GB. I understand to run 4 sticks you need looser timings, is that correct? If I run looser timings that means I'm slightly slower too, yes?

Best to stick to what the motherboard vendor recommends or go to crucial.com and they will have what memory works. I like crucial because they are conservative about what speed/latency you should expect.
3200 vs 3600 memory doesn’t matter that much provided the latency is similar.

 

[PrinceXizor]

This is interesting, kind of the opposite of my last thread on the subject. The advice in that thread was that low CAS was nice if you could afford it.
Increasing order of: CL16 3200, CL18 3600, CL16 3600, etc.
Sounds like you are saying CL16 3200 is preferable over CL18 3600?

 

[MalVeauX]

This is interesting, kind of the opposite of my last thread on the subject. The advice in that thread was that low CAS was nice if you could afford it.
Increasing order of: CL16 3200, CL18 3600, CL16 3600, etc.
Sounds like you are saying CL16 3200 is preferable over CL18 3600?

Latency is what this is all about. The longer that latency is, like CL18, the more speed you need elsewhere to make up for it. So while there are potential advantages to running 4000Mhz or faster memory at slower latency, like CL18, etc, it gets into decoupled infinity fabric clocks, requires tweaking, manual settings, over/under clocking, stability, good motherboard for it etc.

If you want bullet proof fast stuff that will just work, then get the fastest 3200mhz or 3600mhz memory that is CL14 to CL16. They both will operate 1:1 with infinity frabric at these two speeds and so the reality of the faster memory isn't that big of a deal in almost all application, compared to the latency. So when doing this, just get one of those but go for lower latency memory like CL14, CL16. This is more impactful here, since you're staying 1:1 with the infinity clock with 3200Mhz and 3600Mhz speeds.

Very best,

 

[Fanatical Meat]

I’m sort of a dummy regarding memory but I’ve learned that two points of latency basically strip the advantage of one step faster memory for example:
CL14 3200 ram is just as fast as CL16 3600 ram. The bigger “pipe” of the faster memory makes up for the higher latency (time to do something)

As far as real world performance nearly every use case will show no difference between 3200 vs 3600 vs 3700 ram. Benchmarks will show a difference but real world usage won’t be noticeably better on any of them

Faster memory has been better with overclocked CPU but AMD & intel make their current CPU’s run at nearly their peak. This is a good thing because whatever processor you buy will work close to its maximum frequency. Bad part is there isn’t much over locking room.

With a Ryzen processor 3200 CL14 which is hard to find or 3200 CL16 both work great. 3600 CL16 memory isn’t hard to find and it isn’t priced absurdly. Just remember the real world performance increase will be unnoticeable.
Focus on CL16 or lower ram, stick to what the motherboard or major memory vendor recommends for that motherboard.

 

[papapapapapapapababy]

so...i have a 5600x @ 4.85ghz boost and a 32GB kit of 3600Mhz CL18 RAM... should i downclock the ram to 3200 CL16? so the higher bandwidth has no real advantage for games, it seems that magic l3 cache is useless after all amd ( lol J/K) also have a 16 gb dual channel 3200 cl16 viper steel kit that runs like a boss.. also this shit is single rank, could not find a dual rank kit with no silly rgb

 

[MalVeauX]

so...i have a 5600x @ 4.85ghz boost and a 32GB kit of 3600Mhz CL18 RAM... should i downclock the ram to 3200 CL16? so the higher bandwidth has no real advantage for games, it seems that magic l3 cache is useless after all amd ( lol J/K) also have a 16 gb dual channel 3200 cl16 viper steel kit that runs like a boss.. also this shit is single rank, could not find a dual rank kit with no silly rgb

DRAM Calculator for Ryzen v1.7.3 Download

DRAM Calculator for Ryzen helps with overclocking your memory on the AMD Ryzen platform. It suggests stable memory timing sets optimized for your m

www.techpowerup.com

See what your options are with your particular memory. Put in your numbers from your sticks. See what you can get, for timings, by going to 3200Mhz, assuming your infinity fabric is 1600mhz. If you run at 3600mhz on the memory, your infinity fabric is 1800mhz. Beyond that is manually overclocking and decoupling from the infinity fabric's clock. Then just test your system in something that is CPU/Memory intensive (not GPU intensive) to see if it matters if you run your memory at 3600mhz CL18 or if you run it at 3200mhz and tighter timings and less latency at CL16. It may or may not matter enough for you to care. Depends on what you're doing.

Very best,