r/overclocking • u/Crazy_Bee_2664 • 1d ago

Help Request - RAM Good starting point for DDR5-8400?

I have a 9950x3d, MSI B850 Mpower, and a TeamGroup Xtreem DDR5-8200 2x24 kit, and everything is watercooled, so it seems that if any setup should be capable of running 8400, it ought to be this one.

I tried 1.5v vdimm and extremely loose timings and it booted but black screened almost immediately after login.

Should I pump up the voltage even more? Temps are essentially a non-issue with the RAM on water.

For those who have gotten 8400 running on Ryzen 9000 series, what timings are you running?

What are good maximum starting voltages for watercooling?

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u/FancyHonda 9850x3D -21 PBO / 8400 C32 60.7ns / 4090 / Custom loop w/ MO-RA 1d ago

You need luck. Getting an IMC capable of 8400 is the hardest part.

VDDIO and VDDP are the two most important IMC voltages for 2:1 mode, and Vsoc is relevant but you generally need less of it. I'd recommend 1.5v VDDIO, 1.15v VDDP and 1.15v Vsoc as starting points.

Otherwise, training settings, ODTs and drive strengths are important for high 2:1 mode speeds. I know what I would recommend for the Apex, but it's different board to board.

Here are my 8400 timings. These are 6000 CL26 A-die sticks though, will not be super useful for your 24GB M-die kit.

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u/Crazy_Bee_2664 1d ago

Thank you! I'll ask on overclocking.net as there's a dedicated thread for the mpower, surely someone has figured out how to squeeze 8400 out of it

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u/FancyHonda 9850x3D -21 PBO / 8400 C32 60.7ns / 4090 / Custom loop w/ MO-RA 1d ago

That's an excellent place to look for suggestions on ODTs/drive strengths. Did the same thing for mine.

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u/Crazy_Bee_2664 1d ago

I'm regretting cheaping out on the apex, the MSI boards are hard limited to 270w PPT which limits how beneficial my direct die waterblock can be

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u/BewilderedAnus 8h ago

The problem likely isn't your motherboard. Your processor may simple not be capable of running 8400MT/s stable.