Need insight on RAM!

[DivinePhantom]

I am about to make my very first own purchase for a gaming rig as I have a pretty nice budget around $3k-ish. That isn't the main point and what need help/advice on is DDR4 RAM advice/insight, please! I am looking to purchase the G.Trident Royal series of RAM sticks. I plan to purchase only 2 sticks of 16GB of ram and where I'm concerned is the timing speed and latency...?  The timing of the two sticks I plan to buy is 19-20-20-40 with a CAS (whatever that means) latency of 19. I'm comparing this (which probably isn't a good idea, but hey I'm curious why is there change if they're made --practically?-- the same) 4x16GB of G.Trident Royal sticks with speeds of 14-14-14-34 and Gskill doesn't display the CAS latency. What is the real difference and why, but my real question is, if I bought two more sticks of 16GB ram of the same kind from the same seller would it increase the speed to 14-14-14-34?

 

Thank you community.
D†P

Here are the links.
https://www.newegg.com/g-skill-32gb-288-pin-ddr4-sdram/p/N82E16820232822?item=N82E16820232822&source=region&nm_mc=knc-googleadwords-pc&cm_mmc=knc-googleadwords-pc-_-pla-_-memory+(desktop+memory)-_-N82E16820232822&gclid=EAIaIQobChMI0YHuvLvo5AIVGMJkCh20pQCsEAQYASABEgLhN_D_BwE&gclsrc=aw.ds

https://www.gskill.com/product/165/299/1552462216/F4-3200C14Q-64GTRSTrident-Z-RoyalDDR4-3200MHz-CL14-14-14-34-1.35V64GB-(4x16GB)

[Jurrunio]

Timings between kits are only comparable when the frequency and capacities are the same, and vice versa.

 

12 minutes ago, DivinePhantom said:

Gskill doesn't display the CAS latency.

14, it's literally the first number in the timings.

 

12 minutes ago, DivinePhantom said:

if I bought two more sticks of 16GB ram of the same kind from the same seller would it increase the speed to 14-14-14-34?

no, they dont stack. In fact the settings you can run at best will be the settings of the worst performing kit, assuming the memory controller inside the CPU isn't worse than even that.

[DivinePhantom]

So if pricing isn't an issue for me, then grabbing the 14 speed 4x16GB ram sticks is more worth it?

[williamcll]

What cpu are you using? If it's intel you don't need such a high clock.

[WWicket]

1 hour ago, DivinePhantom said:

I'm concerned is the timing speed and latency...?  The timing of the two sticks I plan to buy is 19-20-20-40 with a CAS (whatever that means) latency of 19. I'm comparing this.  What is the real difference and why

 

Ram has a frequency measured in cycles per second, hertz. 

With DDR memory, the reported frequency is twice the actual clock frequency, so the cycle time is (1 second /frequency)*2. 

CAS (Column address strobe) latency is the number of clock cycles it takes to access and return data in one of its columns. So for example, if you had 3600mhz ram with a CL of 19, that means the memory has a cycle time of [1 second / (3,600,000,000 / 2)=] .55 nanoseconds and a delay (true latency) on column address lookups of [19*.55=] 10.5ns. 

 

There are many other important signal timings:

 

When you see something like 14-14-14-34, those are your primary memory timings in cycles: 

CAS-tRCD-tRP-tRAS 

tRCD: (Row address to column address delay) The time it takes between the activation of the line (RAS) and the column (CAS) where the data are stored in the matrix

tRP: (Row recharge time) The time it takes between disabling the access to a line of data and the beginning of the access to another line of data

tRAS: (Row active time) How long the memory has to wait until the next access to the memory can be initiated

 

There are also secondary/tertiary ram timings, for example: tRRD_S, tRRD_L, tFAW.

 

Memory timings (for Intel boards) are set in the MRC of the BIOS. XMP/SPD advertises preferred timings to the MRC. A given MRC may or may not be able to implement a certain SPD-- this is one of the primary reasons for motherboard/ram compatibility issues. XMP/SPD only includes tunings for primary timings. Secondary timings are therefore typcially left at JEDEC recommendations. Many of the secondary timings interact with primary timings in complex ways. Different IC layouts will have different JEDEC standards so memory with identical clock frequencies and primary timings may have different performance...

 

TLDR: Memory timings are complicated... to compare CAS between 2 different ram modules, look at CL / frequency : lower is better

(eg., 19CL/3600mhz vs 14/3200 --> .0053 vs .0044 :: 14CL@3200 is lower CL than 19CL@3600).

 

At a given frequency, tighter/lower primary timings are better. Eg., 1-1-1-8 would be much better than 10-10-10-50, if both had clock frequencies of 100mhz.

[DivinePhantom]

21 minutes ago, williamcll said:

What cpu are you using? If it's intel you don't need such a high clock.

My current build is super outdated and inferior which makes it irrelevant. I plan on purchasing the new 3rd gen Threadripper for my very first PC build.

[DivinePhantom]

19 minutes ago, WWicket said:

 

Ram has a frequency measured in cycles per second, hertz. 

With DDR memory, the reported frequency is twice the actual clock frequency, so the cycle time is (1 second /frequency)*2. 

CAS (Column address strobe) latency is the number of clock cycles it takes to access and return data in one of its columns. So for example, if you had 3600mhz ram with a CL of 19, that means the memory has a cycle time of [1 second / (3,600,000,000 / 2)=] .55 nanoseconds and a delay (true latency) on column address lookups of [19*.55=] 10.5ns. 

 

There are many other important signal timings:

 

When you see something like 14-14-14-34, those are your primary memory timings in cycles: 

CAS-tRCD-tRP-tRAS 

tRCD: (Row address to column address delay) The time it takes between the activation of the line (RAS) and the column (CAS) where the data are stored in the matrix

tRP: (Row recharge time) The time it takes between disabling the access to a line of data and the beginning of the access to another line of data

tRAS: (Row active time) How long the memory has to wait until the next access to the memory can be initiated

 

There are also secondary/tertiary ram timings, for example: tRRD_S, tRRD_L, tFAW.

Memory timings (for Intel boards) are set in the MRC of the BIOS. XMP/SPD advertises preferred timings to the MRC.

XMP/SPD only includes tunings for primary timings. A given MRC may or may not be able to implement a certain SPD-- this is one of the primary reasons for motherboard/ram compatibility issues. Secondary timings are therefore typcially left at JEDEC recommendations. Many of the secondary timings interact with primary timings in complex ways. Different IC layouts will have different JEDEC standards so memory with identical clock frequencies and primary timings may have different performance...

 

TLDR: Memory timings are complicated... to compare CAS between 2 different ram modules, look at CL / frequency : lower is better

(eg., 19CL/3600mhz vs 14/3200 --> .0053 vs .0044 :: 14CL@3200 is lower CL than 19CL@3600).

 

At a given frequency, tighter/lower primary timings are better. Eg., 1-1-1-8 would be much better than 10-10-10-50, if both had clock frequencies of 100mhz.

Just wow. This was pretty sophisticated and insightful. It helped me learn more than I definitely needed to, thank you.

[BigRom]

53 minutes ago, DivinePhantom said:

My current build is super outdated and inferior which makes it irrelevant. I plan on purchasing the new 3rd gen Threadripper for my very first PC build.

Threadripper would need quad-channel memory (kits of 4), what sort of use case do you have for the Threadripper in any case

[Ravendarat]

OP You mentioned that this is a gaming rig, if thats the case then Threadripper is not the path for you to go down, thats more of a workstation style CPU, you would be much better served to be looking at a 3900x or a 9900k depending if you want AMD or Intel. Both of those will perform much better than anything TR4 for gaming given your budget

[DivinePhantom]

1 hour ago, BigRom said:

Threadripper would need quad-channel memory (kits of 4), what sort of use case do you have for the Threadripper in any case

I see. Does quad channel require a min set of 4 or two sets of 4? The use case is mainly gaming and streaming. I do have interest into artwork, but nothing serious enough that I can even think of. To me it just seems like a good idea to purchase for future investment. I am currently in school for computer science but I doubt the Threadripper is needed for that. Just curious, Threadripper is only for individuals who are working with what kind of things? I am pretty ignorant of such things and would be enlightening if some kind individual would like to inform me.

[DivinePhantom]

1 hour ago, Ravendarat said:

OP You mentioned that this is a gaming rig, if thats the case then Threadripper is not the path for you to go down, thats more of a workstation style CPU, you would be much better served to be looking at a 3900x or a 9900k depending if you want AMD or Intel. Both of those will perform much better than anything TR4 for gaming given your budget

So if I'm not into some real workstation stuff it's a better investment to purchase (thinking of getting and 3900x) rather than the upcoming TR? I may have interest in artwork and coding for school, but the TR will not have any real investment for me even if my main thing is gaming and streaming? 

[BigRom]

15 minutes ago, DivinePhantom said:

So if I'm not into some real workstation stuff it's a better investment to purchase (thinking of getting and 3900x) rather than the upcoming TR? I may have interest in artwork and coding for school, but the TR will not have any real investment for me even if my main thing is gaming and streaming? 

The 3700X would be plenty for gaming and streaming if you can't find any 3900X, because AFAIK those are very difficult to find at the moment and its 16-core brother the 3950X hasn't even hit the market yet

[Ravendarat]

16 hours ago, DivinePhantom said:

So if I'm not into some real workstation stuff it's a better investment to purchase (thinking of getting and 3900x) rather than the upcoming TR? I may have interest in artwork and coding for school, but the TR will not have any real investment for me even if my main thing is gaming and streaming? 

Correct, TR is not only a waste of money for you but based on your use, would probably actually preform not as good as some of the cheaper alternatives like the two I mentioned