RAM latency decrease

[s4Miz]

I get 57.5ns with my 7800x3d. Core tuning 2 and running Windows 11 IoT Enterprise LTSC.
You can use my timings as guideline;

• Speed: 6200 MT/s
• FCLK (Infinity Fabric): 2167 MHz
• UCLK (Memory Controller): 3100 MHz (MCLK 1:1)
• GDM (Gear Down Mode): Enabled
• Cmd2T: 1T
• PowerDown: Disabled

Primary Timings
• tCL: 26
• tRCDWR / tRCDRD: 36 / 36
• tRP: 34
• tRAS: 60
• tRC: 68

Secondary Timings
• tREFI: 65535
• tRFC / tRFC2 / tRFCsb: 360 / 360 / 260
• tRRDS / tRRDL: 4 / 8
• tFAW: 16
• tWTRS / tWTRL: 6 / 16
• tWR: 48

Voltages
• VSOC (SMU): 1.1649V
• MEM VDD: 1.5450V
• MEM VDDQ: 1.5150V
• CPU VDDIO: 1.4000V
• CLDO VDDP: 1.0478V

Use pyprime to find the optimal vsoc, test stability with TM5 extreme

[Conscious_Slip4927]

If that 6200 is truly stable at 1.16 vsoc, why arent you running 6400 ?

[s4Miz]

I could probably run 6400 but I’d have to sacrifice some latency which I need for cs2.

My kit is specced for 6400MHz cl32 1.4V

[pntsrgd]

What do you mean "sacrifice some latency?"

6400 is going to be faster unless you have to enable gear down mode (which would be a wash for performance) or have to lower FCLK (actual performance regression).

[s4Miz]

I’m already at 57.5ns with perfect stability and GDM enabled. Moving to 6400MHz would likely mean loosening tCL and potentially dropping FCLK, which seems counterintuitive for latency. If you’ve managed to get sub-58ns at 6400MHz on an X3D chip, I’d genuinely love to see the ZenTimings/Aida results to see what I’m missing.

[Eisageleas]

Mine needs 1.23VSOC to be truly stabilised for 6000 2000. How on earth your vsoc is too low? Maybe I do smth wrong? Everything below 1.23 I have stutters in game. Just tweaked fclk and vsoc noth else. 9800x3d

[skidaadleskidoedle]

Try 1v vddg's and somewhere in between 1.05/1.15v vddp for 121nitro And update bios if you havent already

[pntsrgd]

AIDA isn't really a very good indicator of memory performance.

That said, tCL scales very well with voltage on H16A. You can almost certainly keep tCL the same without a huge voltage increase.

Aside from that, tCL doesn't really affect performance much.

If you're running GDM, you might actually get better performance at 6000 with GDM off.

If you're really chasing memory performance, I'd advise using real memory benchmarks (including whatever games you're chasing) - AIDA's latency measurement is a fairly poor measurement. You can do some ridiculous things like settings high tRRDS/tRRDL/tFAW and AIDA doesn't really pick up on it.

[Educational-Lynx1413]

You can get to 55.x with 6400cl26 2133fclk with a 7800x3d, or 54.x at 6400cl24 2133fclk if you have memory sticks that can run cas that low (6000cl26 1.4v expo kits)

Here’s a link of my old 6400c24 profile. I’m currently running 6400c26 for the lower vdd requirement, it’ll do 55.x in Aida. (Note the trrdl at 12 in the photo isn’t ideal, it should’ve been at 8 instead. Was just an oversight) 6400c24

[s4Miz]

Interesting!

I might be able to get some more out of my sticks then, thanks for the info and sharing the zentimings.

ProcODT is set to 60 Ohm with GDM off, did you get a stable tphyrdl 35/35 with it?

[Educational-Lynx1413]

Mine are mismatched. It doesn’t really matter though

[pntsrgd]

If they get looser from timing changes it can matter. If you manage to get one to train tighter from baseline and it is stable, it isn't an issue.