Downclock 4 x Ripjaws V F4-4000C18-8GVK

[forart.eu]

Hi everyone,
I bought 2 kits of 16Gb DDR4 (F4-4000C18D-16GVK) at a nice price on AZ Warehouse to - temporarily - replace a perfectly working AEGIS kit (F4-3000C16D-16GISB) on my ASUS MAXIMUS HERO VIII (Z170 chipset, which claims to support up to 3800MHz XMP) equiped with i7-7700.
Of course they won't boot at 4000 XMP so, after some test, I've succesfully passed 2x MemTest (v9.4 b1000) cycles @ 3200 / 16-18-18-38 (same AEGIS XMP timings).

I would like to squeeze the maximum speed (note that I don't care much about speed but about latency, due do my DAW/NLE applications) out of these RAMs until I'll renew the whole platform (next will be i5 12500 on z690), but I don't want to overvolt the (CPU) memory controller.

Any suggestion ?

[GSKILL TECH]

Try DDR4-3600 or a lower value until the system can be stable, then you can leave it at that.

[forart.eu]

Try DDR4-3600 or a lower value until the system can be stable, then you can leave it at that.

As said, I don't care mutch about frequency, but I need lower timings.

Are there any recommended combinations, or I have to choose between JEDEC/XMP ones only ?

[GSKILL TECH]

Sure, you can lower and optimize timings once you find the highest stable DRAM Frequency. You don't want frequency to be lower than what the system is natively capable of.

[forart.eu]

I've found this post that gives some interesting infos about a similar kit underclocking on a Gigabyte z690 board:

I've got this same motherboard on bios F5a with a 12600k and my G.Skill Ripjaws 4000mhz CL18 ( F4-4000C18D-32GVK ) worked out of the box with XMP, no issues at all. Also recently underclocked the same kit to 3600 16-20-20-39 to get it to run gear 1 and this setup also seems stable for now. No guarantees on that yet though since I haven't done proper testing.

Hope that helps.

[forart.eu]

Wow, another very interesting find:

Here is my XMP for F4-4000C18D-16GVK kit. Which originally had only 4000MHz XMP profile.With 4000MHz XMP my fabric clock was running at 1000 mhz. so I tuned and created new 3600MHz profile.

[forart.eu]

OK, 1st feedback: the 2 x F4-4000C18D-16GVK kits works without any issues @ XMP 4000 on the Gigabyte Z690 UD DDR4 v1.0 (upgraded to latest F20a BIOS) + Intel® Core™ i5-12600 CPU.

Geekbench v5 results

(live usb) Linux Mint: Gigabyte Technology Co., Ltd. Z690 UD DDR4 - Geekbench Browser

(NvME) Windows 11: Gigabyte Technology Co., Ltd. Z690 UD DDR4 - Geekbench Browser


Then we "played" "played" a bit RAM settings in order to optimize latency and here's results:

MHz	2000	1600	1700	1800	1800	1800
Gear	2	1	1	1	1	1
CR	1	2	2	2	2	1
CL-RCD-RP-RAS	18-22-22-42	18-22-22-42	18-22-22-42	18-22-22-42	16-20-20-39	16-20-20-39
Read (MB/s) ¹	54876	47950	49034	51625	52063	52016
Write (MB/s) ¹	56813	47403	50597	53658	53584	53730
Copy (MB/s) ¹	54785	47197	49909	52497	52962	53324
Latency (ns) ¹	75.2	66.8	63.6	61.1	58.6	58.0
Read ²	1111.29	955.25	1012.95	1071.78	1081.04	1077.83
Write ²	1092.18	914.08	966.84	1027.45	1031.21	1026.48
Combined ²	1145.19	978.53	1040.67	1101.66	1117.48	1104.75
Memory Mark ³	3658	3727	3860	3934	4025	4018
Read Uncached ³	25297	25180	26509	27442	27515	27927
Read Cached ³	36286	36222	36243	35829	36181	34388
Write ³	18681	17134	17945	19101	19478	19307
Latency ³	41	37	35	35	33	33
Threaded ³	53093	44600	47159	49587	50104	50141
Database Operations ³	6666	6466	6854	7015	6945	6941

¹ = AIDA64 v6.75
² = OCCT v11.0.11
³ = PerformanceTest 10.2 x86 Build 1008

Of course now Geekbench has lowered, so now questions are:

1. what's the best setting for A/V editing usage in your opinion?
2. does CR1 really improves ALL performances?
3. can you suggest better settings?

Thanks in advance to all that can/would help.

[GSKILL TECH]

1. Highest frequency with lowest timings while staying within system temperatures ranges and stability.

2. It can but at some point it needs to be increased to achieve stability, similar to any other timing.

3. That is near system capability so anything more you will need to fine tune to see what you can squeeze out of it.

[forart.eu]

Thanks for your replies.

Last question: can other settings (RC-RFC1-RFC2-RFC4-RRDL-RRDS-CCDL-FAW) help to achieve better performances/latencies ?

[GSKILL TECH]

Yes, however requires trial and error testing to confirm stability