# Why does my TRFC have to be so high at 3800?



## terminalinfinity (Jan 4, 2021)

For awhile I had a zen 2 processor with IF that would only stay matched at 3733 and refused to stay stable at 1900.  Got a zen 3 CPU and finally got an IMC/IF that could do 1900.  So I've been working on dialing my RAM down in @ 3800 CL14.  I've run into an issue though where Im having to run significantly higher TRFC than I did at 3733 so much so that I'm basically offsetting all my latency gains from jumping up in frequency.  When I was at 3733 I was able to run the 140ns TRFC equivalent.  (I used Ryzen RAM calculator to get TRFC numbers from expected B-die numbers in nanoseconds)

Now for 3800 Im having to run the 260ns TRFC equivalent.  Dialing it down anymore brings me into error territory.  Is there anything I can do to get this timing down further?  This seems like an awfully big penalty for a 67MHz jump in frequency.

At this point I might as well go back to 3733 because my latency is about the same, Im getting no bandwidth benefit in AIDA64

4X8GB Samsung B-die, Ryzen 5600x, MSI B550 Tomahawk


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## Zach_01 (Jan 4, 2021)

DRAM voltage?

Did you try tRFC 360?
[(tRC x8) + 8]
[(44 x8) +8] = 360

Alt_1
tRC x8
44 x8 = 352

Alt_2
[(tRC x5) + 8]
[(44 x5) +8] = 228

Also instead of RyzenMaster use ZenTimings, its more easy to read









						ZenTimings
					

ZenTimings is a simple and lightweight app for monitoring memory timings on Ryzen platform.




					zentimings.protonrom.com


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## terminalinfinity (Jan 5, 2021)

Zach_01 said:


> DRAM voltage?
> 
> Did you try tRFC 360?
> [(tRC x8) + 8]
> ...





Thanks for the recommendation.  Here it is.

I've dialed all my secondaries back to auto so I can zero in on TRFC.  I'll try using the multiples method you mentioned rather than just trying one notch at a time.
I also dialed back my ProcODT and turned RTTnom off so I could dial back my SOC voltage a little.


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## dgianstefani (Jan 5, 2021)

Give the memory some more juice. This is what I have stable at 1.65v. It's B die, completely safe up to 1.75v if you keep it below 40-45c.


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## terminalinfinity (Jan 5, 2021)

Well, I think I might have nailed it down.
These are just my primaries + TRC.  It took 8 hours w/1usmus custom TM5 profile to find, but it errored.  Im gonna try pushing tRC up one notch and retry the test. (Karhu was error free after 36 hours of testing so I assumed these were stable.)

Of course if tRC was unstable this entire time, it would make total sense that I couldn't tighten down TRFC.


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## Zach_01 (Jan 5, 2021)

Also have in mind that secondary timings and other subtimings are not so esential for a ryzen system.
What makes the most difference in memory performance is 
CL
tRC
tRRDS
tFAW
tRFC

GDM (GearDownMode) when enabled just makes the uneven settings to even. So when you dial a 1, 3, 5, 7, 9... it makes them 2, 4, 6, 8, 10...
Disabling GDM will give memory a performance gain but apparently you will have to reconfigure all settings to find where it is stable.

When going past 1800MHz (1:1:1) for all subsystems its better to disable all power savings of DRAM, SoC and InfinityFabric.

DRAM: PowerDownMode = Disabled
SoC: SoC/Uncore OC mode = Enabled
IF: DF Cstates = Disabled (DF = DataFabric)

The last one maybe a little tricky to find in BIOS/UEFI. Im not familiar with MSI UEFI but look in AMD CBS section, a few menus inside.


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## terminalinfinity (Jan 5, 2021)

Zach_01 said:


> Also have in mind that secondary timings and other subtimings are not so esential for a ryzen system.
> What makes the most difference in memory performance is
> CL
> tRC
> ...


Well, I get to start over lol.  Well at least with primaries.  I began to suspect OS corruption when my bluetooth driver started acting funny, checked with sfc /scannow and yup, corrupted system files.  So now Im re-doing my test OS partition.  Fun.  I should really image the drive this time to make this faster.


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