Sounds like a board firmware limit, otherwise the setting would take, but just be unstable or fail to train/post.

It's probably not a limit of the IMC and it's definitely not a limit of the memory itself.

 

Older generations had stricter tRAS minimums than modern ones.
But tRAS gets ignored below a certain point anyway, so don't fret it too much.

 

Good to know. Do you know the types of workloads most likely to be affected having tRAS higher than its absolutely optimal value?

Very basically, the way I understand it, the way I have my DDR4 set up with its timings 14:15:15:30, nothing will ever be cut off early, but the full amount of time is always taken.

So I'm asking what kind of workloads take less than the full amount of time, a lot of the time

 

tRAS minimum depends on platform/IMC:

AM4 is 21
Haswell-E can run 14
Skylake with ringbus is 28 (LGA1151/LGA1200)
No idea for Skylake-X, but I've seen 24
Alder Lake is 14 x Gear Ratio
Rocket Lake is 14 x Gear Ratio

 

Good to know. When I upgrade I'm considering Rocket Lake or its successor. 80/20% (Rocket/Alder), and have a 70% chance of upgrading. If I don't get Rocket, I won't be getting its successor, but 15th or 16th gen.

Edit: I don't upgrade often - I use parts until they don't do what I want, or take too much time doing it. So if I don't get a 13th gen, I'd probably end up getting a 16th gen ~4-6 months after launch because I like architectural revamps.

2nd gen -> 9th gen -> 16th gen

7s!

The Intel's 9000 series wasn't a big rework, but it has a bunch of little things and the hardware fixes for all those unfortunate exploits. The way they tweaked 14nm allowed for higher clocks than 8000, too.

At 3440x1440 and 2560x1440 75hz and 1920x1080p 120hz, my 3080 is a perfect match to my 9600K at 5200MHz. A 9700K would've been better, but when I built the system it was meant to be an ITX. Damn motherboard broke! Anywayyy, I'm going on and on

 

According to buildzoid latest video on RAM timings and the description of tRAS in my motherboard UEFI (X299 Dark), the lower bound for tRAS is tCL+tRCD+tRTP. Anything lower should be ignored by the memory controller because it makes no sense. I guess you can think of this timing as an artificial limiter kind of like tFAW, so setting tRAS to tCL+tRCD+tRTP is like setting tFAW to tRRD_S*4, i.e. the minimum possible value. Anything more will add unnecessary* delay. So even if you run tRTP at the lowest possible value on DDR4 which appears to be 5 according to the JEDEC datasheet, it gives you plenty of play for tCL+tRCD even if the minimum tRAS is 28 on your motherboard. Reason I put a star next to unnecessary delay above is because tRAS also drives tRC (on Intel tRC = tRAS + tRP and you can't change it, unlike on AMD), and some dies are not able to run the minimum tRC = tRAS+tRP = tCL+tRCD+tRTP+tRP. On B-Die it doesn't seem to be a problem but I had some crappy OEM Rev. E a while ago and I could run very low tRP but that required very high tRAS, or I could run high tRP and lower tRAS, so in the end that kit was limited by tRC and needed that "artificial" looser tRAS just to satisfy tRC.

 

Interesting stuff. My tRTP is 6. I think it ran at 5 too, but I returned it to 6 because I didn't know if it was one that should be even with my tCL 14. And it's just +1... Does +1 make an impact? If it's drastic like changing the command rate, I'd do it. I wish my IMC was strong enough for CR1, but I'm stuck at 2, even at lower frequencies.

The formula you mention at the beginning (tCL+tRCD+tRTP) - with my timings it gives the value 35 for tRAS. My RAM won't perform faster with tRAS lower than 35?
I don't have any experience with high tRAS settings (I've just never had it high, benchmarked, then lowered it. It's one of the easy timings I did in the past when I knew absolutely nothing.)
But recently I've tuned up a 2500K with DDR3 2133 10-12-11 with 22 and 24 tRAS (I'm not sure which to settle on, both are stable). I could swear AIDA64 latency is lower by 0.2ns, maybe more, compared to tRAS 31

 

Z690 is just a much better platform to overclock RAM on, since tRCD and tRP are finally detached, and tRAS can go much lower than before, so long as the RAM isn't limiting itself internally.
Many of the other timings can be tightened a bit better as well, and it seems that the CPU gives a performance boost on top of the RAM itself.
You can get more than the maximum theoretical bandwidth limits for RWC speeds in Gear 1.

 

I've been thinking of possibly upgrading my rig to Intel's 13th gen when it comes out, if it's good. And I have no reason to think it won't be. I really enjoy tweaking RAM (tweaking everything, really), and what you're saying now makes me want a 13th gen. I don't need a performance upgrade immediately, but getting a new machine, a fast machine, and getting its parts all working in perfect harmony? Tempting - to build and to have and to use lol.
You helped me a lot with advice and info while I was overclocking the RAM in the system that this thread's about. You might remember, I bought another 16GB kits of it a while ago (Patriot Viper Steel 4400 C19 Series RAM), and for performance reasons it's in a drawer. Neither the 9600K or 3700x benefit from it! 9600K because I don't often need more than 16GB RAM, and dropping from 3900 to 3700 to keep the same timings wasn't great. The newer kit does the older kit's timings at 3800MHz, another 100 is lost from the daisy chain motherboard. The 3700x... poor thing... it's broken and always has been apparently. Anyway, the best it can do is 3200MHz 14:18:18 CR1 with my 32GB kit of Corsair Vengeance LPX 32GB (2x16GB) DDR4 3600 C18. And for that CL14 at 3200MHz? SA voltage has to be set to no lower than 1.28V (I give 1.3) to enable fclk to hit its maximum frequency of... you guessed it: 1600MHz. Probably more than you needed to know to answer this question: is the kit I have a good option for z690/790? I'm thinking of getting the unlocked 6 core. If they make the 6 core into an 8 core (like when 4 cores turned into 6 in 9th gen), I'd get that. The one in 3rd place

If my patience wins over my upgrade urge though..., a new desktop won't come til a bit later, probably 16th gen. My laptop is a Surface Laptop 2 with 8250u, and its mouse fell out when the thing fell 2 feet off the back of a chair onto carpet (it shouldn't have come out - I'll call it broken). Anyway, if replace that (I kind of have to) with something pretty fast (I don't necessarily have to), my desktop would be a more than capable gaming rig until 16th gen comes out (if Intel sticks to their product release schedule). I hate when things break

 

其他人有這個 tRAS 的下限嗎？

我的主內存時序是 14-15-15，我才知道如果將 tRAS 設置為低於 30，它可以提高性能。所以我嘗試了 28 - 沒有問題。嘗試 26（鍵入 26）- 框重置為自動。嘗試 28，然後按“-”降低值 - 再次直接下降到自動！

我可以發誓我見過很多較低的 DDR4 tRAS 時序。

28 是我的主板強加的人為硬限制嗎？tRAS 的最小值是否取決於內存時鐘速度？特別是對於像 2133 和 2400 這樣較慢的速度，tRAS 最小值 28 似乎非常高......
[/引用]YES! 28...........