Hey, so I just installed my new PC and I decided to go for 8400mhz ram and tune it down to 8000 2:1 mode.
I literally just followed ChatGPT's advice and a few posts online here are my results.
Please feel free to help me out with potential changes to the settup or other tests to do
4 Comments
You will have a hard time make this ram run stable on ur 9950x3d 👀
You might even be better off getting back to a 1:1 ratio (6000 without overclocking UCLK) and a lot tighter timings.
From there, you could potentially overclock the UCLK a bit to make it run a little faster. But you’d need to research this a bit bc it can be quite finnicky and unstable. 6200MHz is probably achievable on most kits, with some luck you might get it stable at 6600.
I am recommending this alternative because 2:1 ratio adds about 9ns of latency according to AMD.
Latency at 6000 CL30 ≈ 10ns
Latency at 8400 CL40 ≈ 9.5ns
Add the ratio delay on top of it and you’ll have about 8-9ns more delay than running 6000 CL30.
Very nice, especially with gear down mode off.
You can tighten your primaries and likely floor tRCDWR to 16.
All of the sub-timings are not tuned.
You probably don’t need 1.25 vSoC, but I would tune that as the last step.
Your PHY bus is trained quite lazily, but I wouldn’t tighten prior to tuning everything else.
Before anything else try 8200 because 8000 vs 6400 is hit and miss where as 8200 is basically always better than 6400
And those timings are terrible to say the least… you should just google image search for AM5 8000 and then compare a few and try the settings they used but dont change the impedances / resistances or the voltages to theres keep yours