# DDR4 Overclock



## TAITO (Jun 4, 2019)

Hello

I made OC to memory RAM up to 3400Mhz CL 15-17-17-35 2T

from standard 3000MHz CL 15-16-16-35 2T

Now I would like to lower the timings






Which of these timings can i lower more?


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## dgianstefani (Jun 4, 2019)

I doubt you'll be able to achieve much if you've already done an OC. 3000/15 is not Samsung B die so good luck.


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## TAITO (Jun 4, 2019)

My ram memory is a samsung d-die with 1.5V
I would like to lower the timings as much as possible


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## MrGenius (Jun 4, 2019)

TAITO said:


> I would like to lower the timings as much as possible


Then do that. And test for stability with MemTest64. I recommend 20 loops minimum with 75% of your total GB(so 12GB or 12288MB). If it will pass that with 0 errors it's 100% stable in my book.

There no magic numbers for all sticks of RAM(even the exact same type, brand, etc.). They all vary in how much voltage they require, the frequency they'll run at, and how tight the timings can be to remain stable. The motherboard and CPU play a roll too. Different RAM will run differently on a different motherboard and/or with a different CPU. LOTS of variables.


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## TAITO (Jun 4, 2019)

Okey so i did the test with MemTest64

This is the result


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## cstkl1 (Jun 5, 2019)

reduce trtp to 3  since you are running tras 35, tcl 15 and trcd 17
twr try 8 or 10
twcl try 9
trrd_s try 4
tref try 26520 , 32727 or just max it out. 
trfc i suppose thats the lowest you can go.
thats about it.


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## phanbuey (Jun 5, 2019)

trfc 'if' you can go lower is probably priority, you may be able to get away with a higher TREFI as @cstkl1 mentioned.


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## cstkl1 (Jun 5, 2019)

phanbuey said:


> trfc 'if' you can go lower is probably priority, you may be able to get away with a higher TREFI as @cstkl1 mentioned.


just noticed another thing on his screenshot
his rtl/iol are all over the place.


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## phanbuey (Jun 5, 2019)

I usually don't mess with those unless i have a week of my life to lose...


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## cstkl1 (Jun 5, 2019)

phanbuey said:


> I usually don't mess with those unless i have a week of my life to lose...


its actually pretty important for dual channel config. you can reduce your vccio/vcssa while maintining high cpu clock.


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## GorbazTheDragon (Jun 5, 2019)

Try to pull down RFC and increase REFI.

Other secondaries you want to try to decrease. Tertiaries you maybe can play with but they tend to be very finnicky with little performance difference.

You can use something like the ryzen timing "calculator" to find timings to use as a reference. https://rog.asus.com/forum/showthre...mus-V-Formula-UEFI-OC-Tuning-Guide#post131516 This thread might also be useful even though its for DDR3.


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## TAITO (Jun 5, 2019)

I have restored all timings to the standard auto because a lot of errors appeared in MemTest.
Now I was able to steadily reduce trfc to 310
Before this everything on the settings from the first timing screenshot was not stable,
trfc was set to 480 and in the MemTest program full of errors.
Now I have to lower these timings again. What do you think from which timings to start lowering?

Thank you all for help


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## cstkl1 (Jun 5, 2019)

TAITO said:


> View attachment 124352
> 
> I have restored all timings to the standard auto because a lot of errors appeared in MemTest.
> Now I was able to steadily reduce trfc to 310
> ...


last is tref
trfc should be the 2nd last
3rd last is twtr

trtp should be first
tfaw and trrd simultaneously 2nd

the rest actually doesn't matter

3rd timings u should as those on dual channel but afaik only 4k and above they come to play.


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## TAITO (Jun 5, 2019)

GorbazTheDragon said:


> Try to pull down RFC and increase REFI.
> 
> Other secondaries you want to try to decrease. Tertiaries you maybe can play with but they tend to be very finnicky with little performance difference.
> 
> You can use something like the ryzen timing "calculator" to find timings to use as a reference. https://rog.asus.com/forum/showthre...mus-V-Formula-UEFI-OC-Tuning-Guide#post131516 This thread might also be useful even though its for DDR3.



Ok, so now i'm going to lower trfc and increase refi, if I do it will give me more performance?
Which of these timings are secondary and other tertiary?

TRFC : 310 stable
TREFi : 26520 stable

Can I increase it to a higher value other than 32727 ?
(ASRock Timing Configurator does not detect 32727 TREFs while in bios it is set and PC boots windows)

I tried to reduce these values:

trtp: 3
twr: 10
tcwl: 9
trrd_s: 4

but PC does not boot windows and restores factory settings in BIOS

trtp: 8 stable ( reduce more or leave? )
twr: 10 stable ( reduce more or leave?  )
tcwl: 13 stable ( reduce more or leave? )
trrd_s: 6 stable ( less than 6 PCs will not start )




Now the timings look like this

So now what to do next?

Please help me


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## MrGenius (Jun 5, 2019)

tRFC: As long as you can get it without producing errors.
tREFI: Basically no more than 2x-3x the auto setting is recommended(though you might be able to get away with more than that). There's a mathematical formula to determine that...let me see if I can find it again.

tREFI(JEDEC/auto/default) = 7.8ns = DRAM Frequency(actual MHz, not effective "MHz" or MT/s, it's whatever CPU-Z says, or for example 3400 ÷ 2 = 1700MHz) x 7.8

So...

1700MHz x 7.8 = 13260 tREFI(JEDEC/auto/default/7.8ns)
13260 x 2 = 26520
13260 x 3 = 39780

You should also consider tweaking your voltages. That can help a lot. Here's another good guide.


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## TAITO (Jun 5, 2019)

Thank you very much MrGenius

Currently voltage is 1.5V
VCCSA 1.2V
VCCIO 1.2V

TREFI 39780 stable


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## SiRoCu (Jun 5, 2019)

Before OCing RAM you should choose the RAM slot as the standard first, for 2 sticks will be A2 and B2 DIMMs. 

For timing try tREFI at the max value 65535 it reduce access time and improve READ and WRITE, this mean COPY also.


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## phanbuey (Jun 5, 2019)

can you go lower than 15-17-17?  have you tried 15-16-16? 15 all with the new voltages on SA and IO?

Also, have you tried flipping the timings?  go 16-15-15 or 17-16-16? some kits perform better with this configuration.


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## TAITO (Jun 7, 2019)

trefi 39780 vs trefi 65534

Now I want to lower the tertiary timings

Can somebody help me ?

Thank you


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## cstkl1 (Jun 7, 2019)

based on the asrock timing configurator list i would do
10, 327, 6,4,8,3,8,16,9

btw u wont see much of a difference with this
twcl will see slightly better latency and bandwidth
trefi, tfaw and trf are the major ones

rest more to stabilizing. 

are you using bdies??
u should try 16,16,16,36 with twcl 9 first


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## TAITO (Jun 7, 2019)

15-16-16
16-15-15
16-16-16
17-16-16

PC will not start

My ram is Samsung D-DIE

TCWL 9 PC will not start

i can try set TCWL 10, 11, 12 or leave value at 13 ?

Finally the timings look like this :





Make more changes or leave it?


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## cstkl1 (Jun 8, 2019)

example 2nd timings i run but on x299

was a basket to get this stable again from bios 0802 to 1503. Asus changed a few things. But seriously good job Asus.. a lot of improvement.


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