Hey all, I made a bit of a rookie mistake on my new 9950X workstation build and could use some insight.

I picked up 2x48GB sticks of Kingston Fury Renegade DDR5-6400 for my VFX rig, planning to eventually double the capacity down the line. I'm running them on a Gigabyte X870E motherboard with an MSI Ventus 5090. The RAM runs fine with XMP enabled, and everything is stable with good temps and solid benchmark results.

However, I'm currently running a 2:1 memory-to-infinity fabric ratio (FCLK), and I can’t seem to get a stable 1:1 config at this speed. I’ve done quite a bit of reading and testing, but no luck so far. Latency is around 66ns, which seems okay—but it does raise the question:

Is 1:1 even possible with 2x48GB at 6400MHz on this platform? And more importantly, is it worth chasing?

I’ve tried downclocking to 6000MHz to run 1:1, but overall benchmark performance actually drops compared to 6400 at 2:1. I’d return the kit and try something else, but that’s not an option at this point.

I’ve included my timings and latency results below for reference. Any advice or insight,especially from folks running similar setups would be greatly appreciated!

Thanks in advance!

14 Comments

  1. nightstalk3rxxx

    I highly doubt you lose performance on 6000 1:1… 2:1 is only really faster at 7800 or so.

  2. Just_Maintenance

    You will probably need to pin VSOC to 1.3v. If it still can’t do it then you will just have to forget about it.

    If you aim to double your memory down the line (by adding 2 more 48GB sticks) there is absolutely no way to do 6400.

    Also, don’t just look at AIDA. The memory benchmark is NOT representative of real world performance.

  3. Yellowtoblerone

    Ok this platform? Yes absolutely. On yours? At what voltages did you ran 3200 uclk? If you’re maxed and it still wasn’t stable then you just didn’t luck out on the lottery

  4. GeneralKonobi

    My 7600 and B650 board are running 6400 1:1 no problem. You probably need more VSOC voltage or you lost the IMC Silicon lottery.

  5. volnas10

    Very unlikely, but you could try 6200 at 1:1 if 6400 doesn’t pass stress tests.

  6. Nunkuruji

    On my 9950X3D 2×48 I did not have any luck with 6400 1:1, no sane VSOC was stable, seemed the IMC was limited. Dropped it to 6200 and tightly tuned it, referring to some of buildzoids content for a baseline.

  7. astrobarn

    It’s possible, I’m running 2×48GB at 6400 32-38-38-38 1:1 on a 9950X3D stable in Y-cruncher and OCCT.

    I’ll send you my zentimings.

  8. D33-THREE

    Not exactly apples to apples ..but

    9800X3D on B650E Taichi Lite

    2x32gb KLEVV EXPO 6400 CAS 32 @ 6200 CAS 30 1.35v DDR voltages using Buildzoidz easy Hynix 6000 timings. 1.2v SOC. LLC 2. FCLK 2067. MCR PDM GDM all left enabled. AGESA default.

  9. Balrogos

    I agrre with the boi just use 1:1 6000mhz depends on workload/games try tune your timings, TREFc is like 70% of performance in games. And dont belive every benchmark or you mean for example AI/rendnder test done by yourself

  10. the_lamou

    Yes, it’s absolutely possible. My 9950x server is currently sitting very happy at 1:1 6400 96GB at stock Expo+ (voltages turned down some, a couple of subtimings turned up.)

    If you look at the posts on my profile, the last one I did here is my timings — I basically copied them over from my 9950X3D desktop. I haven’t run any benchmarks, because Linux benchmarks mostly suck and getting them to play nice is a chore (thanks, MSI, for not including ANY Linux drivers), BUT I manage about 8 tokens/s on 24B Q8 LLMs with pure CPU, which is damn reasonable.

  11. Sabbath196

    Is anyone using these specific sticks? So weird that I am having trouble then. Could it be heat? Im not having issues with heat elsewhere though. Here is the rig
    https://imgur.com/a/BgaRtRc

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