Installed new ram corsair 4000 it has a CL of 28????

[krag]

I upgraded my ram sticks from 32Gb of 3200 to 32GB of 4000 Corsair Vengeance. My CL is at 28? The sticks have Cl of 18, so why is it at Cl28? I have everything in my bios set to Auto except the speed of 4000Mhz. Here is a shot of the CUPID and a pic of my bios.

Q. Is this normal?
Q. Do I need to manually adjust the CL to 18?

Apologies for the blurry pic my phone had a hard time auto focusing due to my 120Hz monitor.

My motherboard is the one in my siggy. Asus 570X-E Strix with bios v.1409

 

[Zerileous]

You'll need to enable the DOCP or XMP profile for the memory in the BIOS to get it to run at the advertised speed and timings. However with a 3800x you probably don't want to run it at 4000MHz. The "Infinity Fabric" clock reflects the speed of the memory controller onboard the CPU,m as well as the interconnects between cores. The best performance is usually achieved with a ratio of 1:1 between the memory speed and the fabric clock, because it minimizes latency. Most any chip (Zen 2 aka 3000 series) will do 3600 and some will go up to 3800. Mine will only do 3733MHz. After 3600 you have to manually set the ratio to 1:1 or manually set the clock to match the memory clock.

Honestly going back to the 3200 and returning the 4000 sticks might not be a bad idea. On the other hand 4000MHz sticks are probably probably pretty good so if so motivated you could definitely manually set up the timings for 3733MHz or 3800MHz or whatever your CPU will do. At least in gaming though the performance benefit is slim, maybe 1% FPS in CPU bound scenarios from 3200MHz to 3600Mhz and returns diminishing from there. I believe this article has some further guidance https://www.gamersnexus.net/guides/3508-ryzen-3000-memory-benchmark-best-ram-fclk-uclock-mclock, but I can't read it right now.

 

[Blaylock]

Krag, can you post a pic of your SPD tab. This will show the DOCP or XMP profile(s) along with primary and secondary timings for those sticks.

If you are still having issues Hero Denarian made an excellent write up on how to find a great starting point with Ryzen using Thaipoon Burner and Ryzen DRAM Calculator.

 

[mackerel]

Like others said, turn on XMP to load the timings from the module. If you only change the speed then chances are the mobo extrapolated JEDEC standard timings beyond maximum defined 3200, which are pretty slack.

 

[EarthDog]

I've never seen CL ratings that high for JEDEC speeds... holy cow. What Mack said is spot on.

I agree with Z... 4K RAM on Ryzen is a waste since you can only tie FCLK 1:1 to memory speed anyway. Return the sticks and get CL14 3600 sticks. Set xmp and go.

 

[mackerel]

I've never seen CL ratings that high for JEDEC speeds... holy cow. What Mack said is spot on.

I agree with Z... 4K RAM on Ryzen is a waste since you can only tie FCLK 1:1 to memory speed anyway. Return the sticks and get CL14 3600 sticks. Set xmp and go.

Just looked it up, middle bin 3200 is CL22 (nothing faster defined), which would scale up to CL28 at 4000.

I don't know if this ram does it, my Kingston HyperX 4000 ram has two XMP profiles, one at 3600 and one at 4000. The 3600 actually works better in multiple loads on both Intel and AMD systems, presumably because it better timings. They got relaxed too far to hit 4000.

 

[EarthDog]

I'm not sure what you mean by 'middle bin'. 3200 CL22 is JEDEC/compatibility type stuff. What the motherboard does with timings on auto/above the profile is up to the mobo. Essentially, that is a JEDEC 3200 profile for compatibility.

EDIT: I forgot that 3200/CL22 is a defined JEDEC specification.
https://www.tomshardware.com/news/first-native-ddr4-3200-ram-century-micro,39804.html

 

[tRidiot]

So how much does the CL actually matter in daily life? Even in gaming? Yes, on benchmarks we can see a difference... but is there a real world example to look at? I dunno, I've never understood most of the memory timing stuff, I've read and re-read and tried, but it doesn't seem to stick, for me.

 

[EarthDog]

So how much does the CL actually matter in daily life? Even in gaming? Yes, on benchmarks we can see a difference... but is there a real world example to look at? I dunno, I've never understood most of the memory timing stuff, I've read and re-read and tried, but it doesn't seem to stick, for me.

Enough to warrant not running at those incredibly high timings. For the most part, JEDEC and those extremely high timings are there for compatibility reasons, not for daily driving. As was said above, you're likely on auto and just changed the speed instead of enabling the XMP/DOCP/ADOCP profile in your BIOS.

There are several reviews/articles out that show the difference between say 2133 CL20 and 3600 CL16. I googled "Ryzen Memory scaling" and came up with the one below!
https://www.gamersnexus.net/guides/...n 3000 chips,extreme overclocks up to 5100MHz.

Can you please post up a screenshot of the SPD tab for that memory?
Can you confirm you set the speed on auto and left the timings and such on auto?

 

[tRidiot]

Can you confirm you set the speed on auto and left the timings and such on auto?

He said he set everything to Auto except the speed which I assume he set manually.

 

[EarthDog]

Ooops. I thought you were the OP since you jumped in asking that question...lol

 

[Zerileous]

Timing and speed are really two sides of the same coin, to an extent. The number in a timing is a number of clock cycles. Therefore at a given speed, say 4000MHz, for example, 18 clock cycles may be less time than say 16 clock cycles at 3200MHz. This can be expressed in a latency chart such as this:

https://imgur.com/2Xed9gn

. Of course the other factor in a Ryzen system is the infinity fabric clock which impacts inter-core latency as well, so just running 2666MHz at CL14 would not equate to better performance than 3600MHz CL18, even though the latency on the chart is lower.

 

[tRidiot]

Timing and speed are really two sides of the same coin, to an extent. The number in a timing is a number of clock cycles. Therefore at a given speed, say 4000MHz, for example, 18 clock cycles may be less time than say 16 clock cycles at 3200MHz. This can be expressed in a latency chart such as this:

https://imgur.com/2Xed9gn

. Of course the other factor in a Ryzen system is the infinity fabric clock which impacts inter-core latency as well, so just running 2666MHz at CL14 would not equate to better performance than 3600MHz CL18, even though the latency on the chart is lower.

that helps me a good bit, thanks for that chart. Maybe it's just I am a visual person and that helps me organize the relationships between Cas latency and speed.

So if I'm reading this right, my CL16 3600MHz RAM has an E of 8.89, while 4000Mz RAM would have to have a CL of 18 to even be close (9.00). My understanding is the faster you push the RAM, the more you have to 'loosen' the timings to keep it stable, so it's much more difficult to achieve a CL18 with 4000MHz RAM.

Is that at least kinda along the right path?

 

[EarthDog]

Is that at least kinda along the right path?

Yep!

Now, let's get back to taking care of the OP.

 

[krag]

Well I enabled DOCP and manually set the speed to 3733 as recommened earlier. Next step is to open the SPD tab. I am off to work so it wont be until tomorrow. I work swing at a electronic repair shop. We repair all comcast xfinity routers and modems. even though I get paid by comcast, I do not like comcast.

Thank you for all of your help brothers.

 

[EarthDog]

Those timings look a lot better!

 

[Zerileous]

For sure that looks much better.. If you have the desire I would imagine that you could run somewhat tighter timings at 3733.
The best way to go if you're ready to head down the rabbit hole is to use a program called Taiphoon Burner to determine what IC your memory uses, and then we can get a ballpark of what settings it can run.

I'll preface the next part with the statement that I'm pretty new to this myself, there are some here with a lot more experience at this, but I'll share what I've learned to the best of my knowledge.

I'm guessing your kit would handle CL16 3733 with some tweaking. Some of this is trial an error though, using something like AIDA64 to test results. Some people have had luck lowering the tRFC quite a bit and seeing a few percentage points improvement in FPS (https://www.gamersnexus.net/guides/3333-memory-timings-defined-cas-latency-trcd-trp-tras). My board defaults this setting to something in the 600s, but I can run it at 420 for 3733 and 300 for 3600 (both at 1.45v). You can also probably lower tRAS and then set tRC to tRAS+tRP.

I will say it is possible to pay out too much in secondary / tertiary timings in exchange for primary timings. For example to run 3733 CL16 I needed to set tRFC to 653 and the command rate to 2T, however performance was worse than setting CL18, tRFC 420, CR 1T. Also based on the chart linked above I would be better off running 3600 C16 than 3733 C18, but that doesn't account for everything and I should probably do more testing to see if that holds true.

I couldn't find a review of a Corsair kit with the same timings as your kit, but I did find a different brand with similar timings. It may be based off of the same memory IC. https://www.overclockers.com/forums...B-2x8GB-DDR4-4000-CL18-TF10D416G4000HC18JDC01. 3733 wasn't tested here but there is a set of timings for 3600. The memory may be able to run those timings at 3733 with 1.4 or 1.45 volts.

 

[Woomack]

Corsair uses all available IC. Literally everything so it can be Nanya or Spectek too. To give any advice will be needed more detailed info about the IC so either the Thaiphoon Burner screenshot or full IC number.
On the other hand, there won't be any significant performance improvement when the memory runs at 3733 CL18. Maybe 1-3% in some games and that's all. All these significant differences are between 2133-2666 and 3600+ or 3000-3200 single rank vs 3600+ dual rank ... and also only in some tests/games.

 

[krag]

Well, I took E-Dog's advice and just now bought this...ooooooo...I,m stok3d!


G.SKILL Trident Z Royal Series 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 3600 (PC4 28800) Intel XMP 2.0 Desktop Memory Model F4-3600C14D-32GTRG

 

[Woomack]

So I guess that topic is closed as you won't get anything better for your PC
It should work at 3733 at XMP/DOCP settings or at a slightly higher voltage like +0.05V.