MSI Tomahawk X870 & 9800X3D

[DebenPoison]

Hi all,

Are there any good tutorials or youtube videos/threads that give a good run through of:

1) Enabling PBO on the MSI Tomahawk X870 / Overclocking the 9800X3D
2) Memory tweaking - including FCLK and UCLK ratio

I have an especially for common piece of kit, with this board and CPU, as well as 64GB G Skill DDR5 6000Mhz CL30.

Quite a popular set of hardware yet I'm not finding very many guides for enabling PBO and getting the most out this memory and CPU.

At stock with everything pretty much auto, I'm getting boost on the CPU to 5225mhz however I'd like to drill down on the memory a little more outside of just setting the EXPO profile.

Also I've read folks setting a 200mhz and -30 curve optimizer ; I'd love a bit more guidance on that as well as the FCLK and UCLK settings. Is the 2000mhz for FCLK and 3000mhz for UCLK pretty standard? I thought a 1:1 ratio here was best for example.

 

[ir_cow]

I would do all your memory overlooking voltages and tweaks separately from CPU. One you have both locked in independently, the next step is to combine them. That way at least you what the system is capable of. The more wheels you have going, the harder it is to diagnose a issue.

 

[Zach_01]

You are running 1:1 ratio for UCLK:MCLK. Both are at 3000MHz.
The difference with AM4 platform is that FCLK is uncoupled now from the other 2.
For example on AM4 with 3600MT/s kit those speeds would be 1800:1800:1800 (1:1:1). That gives the best latency. But since IF (FCLK) can’t keep up with the other 2 on AM5 (Zen4/5) the common settings are 2000:3000:3000 (2:3:3 ratio)
You can try to increase FCLK a step or more and test the results. Latency and maybe gaming benchmarks.
There a few CPU/Board combos that can achieve 2133:3000:3000 or even 2200 for FCLK but for sure it’s not common.
Some are trying to preserve the 2:3:3 ratio and go for something like 2133:3200:3200 (6400MT/s), or 2066:3100:3100 (6200MT/s)
Personally I don’t see it necessary. If you want to tune these you just trying to find the highest FCLK (2066-2200) and also the highest possible UCLK:MCLK speed.
You may end up to something like:
2066:3200:3200
or
2200:3100:3100
which breaks the 2:3:3 ratio but only benchmarks can reveal if it’s best or not.

For CurveOptimizer settings things are pretty much straightforward. Especially for single CCD CPUs.
Most Zen4 and Zen5 can sustain a -20, even -30 steps on the V/F curve. Each step is -3 to -5 mV.
So at -20 magnitude you’ve done a undervolt of 60-100mV across the V/F curve. Meaning less voltage for the same frequency or more frequency for the same voltage.
This applies through out the whole range of frequency.

On the other hand the boost overdrive (+25~200MHz ) refers to the top end of the V/F curve. If now your top frequency is 5225MHz it will add 200MHz if you max out the setting (steps of +25MHz). This has no impact on middle frequencies. Only on top.

Like @ir_cow said you have to test all these individually and not all together at once or you’ll be lost.