Question Correct timings for my RAM (Corsair can't help me) ?

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cheekykid

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I am looking for some help to find the correct timings for my DIMM's and Corsair doesn't seem to know. Their reply is: "Unfortunately, we are unable to assist with providing the specific timings for underclocking/overclocking memory kits. Outside of the applications suggested, I advise reaching out your motherboard's manufacturer for further assistance. Enjoy your day!"


I have four 16GB ‎CMH32GX4M2Z3600C18 paired with my AMD 5900X. Due to my cpu I can only run them up to 3200Mhz.

"I think" the correct timings for 3200Mhz are as follows:
  • CAS Latency (CL): 16
  • RAS to CAS Delay (tRCD): 20
  • Row Precharge Time (tRP): 20
  • Cycle Time (tRAS): 38
  • Set the DRAM Voltage to 1.35V.

    I am not sure what should I put for tRCDWR which BIOS has set it at 22.


    Does anyone know if am on the right path here?
 
KingLoki

KingLoki

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Yeah should be fine. Boot it up and run cpu-z program and check memory inside there. When you are overclocking memory to push it faster, the timings normally loosen up anyways.
 
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JohnBonhamsGhost

JohnBonhamsGhost

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cheekykid said:
If I enable XMP that puts my ram at 3600Mhz. Would the timings for 3600 be also good for 3200?
Click to expand...
have you enabled XMP and found that the 3600Mhz profile is not supported?
or are you just guessing that this motherboard doesn't support anything above 3200Mhz?

most CPUs & motherboards may have a default minimal supported rate stated in their specs,
but will still run RAM manufacturer profiles.
 
faalin

faalin

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According to Corsairs webpage they are a 3600Mhz 18-22-22-42.

You will have to try tighter timings @ 3200Mhz, drop down to 17-22-22-42, if that works then try 16-22-22-42, if not then move back to 17. Leave the 17 and try dropping down to 17-21-22-42 and so on. There are no golden numbers that every ram stick will run at, you have to test and see where YOUR's will work at.

Being that you are running 2 different kits together and 4 sticks im guessing you wont get much under the ratted specs.
 
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cheekykid

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JohnBonhamsGhost said:
have you enabled XMP and found that the 3600Mhz profile is not supported?
or are you just guessing that this motherboard doesn't support anything above 3200Mhz?

most CPUs & motherboards may have a default minimal supported rate stated in their specs,
but will still run RAM manufacturer profiles.
Click to expand...

When I enable XMP the speed goes to 3600 and the system runs though I haven't done any testing as to how stable it would be.

I been reading for a while and I still can't decide between 3200 and 3600
 
kanewolf

kanewolf

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cheekykid said:
I am looking for some help to find which are the correct timings for my DIMM's and Corsair doesn't seem to know. Their reply is: "Unfortunately, we are unable to assist with providing the specific timings for underclocking/overclocking memory kits. Outside of the applications suggested, I advise reaching out your motherboard's manufacturer for further assistance. Enjoy your day!"


I have four 16GB ‎CMH32GX4M2Z3600C18 paired with my AMD 5900X. Due to my cpu I can only run them up to 3200Mhz.

"I think" the correct timings for 3200Mhz are as follows:
  • CAS Latency (CL): 16
  • RAS to CAS Delay (tRCD): 20
  • Row Precharge Time (tRP): 20
  • Cycle Time (tRAS): 38
  • Set the DRAM Voltage to 1.35V.

    I am not sure what should I put for tRCDWR which BIOS has set it at 22.


    Does anyone know if am on the right path here?
Click to expand...
Boot at default clock. Use CPUz to see all the timing tables in the SPD tables. There is probably a 1600 base clock profile.
 
BFG-9000

BFG-9000

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cheekykid said:
When I enable XMP the speed goes to 3600 and the system runs though I haven't done any testing as to how stable it would be.

I been reading for a while and I still can't decide between 3200 and 3600
Click to expand...
Given that 3600 is considered the "sweet spot" for Zen 3 and nearly every example can run that, I would just do the testing.

It's not like you wouldn't have to do stability testing when tuning timings for the 3200 speed unsupported by the memory manufacturer, is it? In either case you are overclocking--either running the CPU memory controller at a faster than supported speed, or memory at slower speed but tighter timings than is supported, and that means trial-and-error until it works.

The whole point of XMP is to minimize the trial-and-error part, so if you had wanted 3200 memory you should've bought 3200 memory.
 
KingLoki

KingLoki

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The read and write speeds on the 3200 look good. Very close to 3600mhz. I would play a bit with the timings, very lightly and re-run tests. Drop the top timing of 18, down to 17 and run test. If no problems then try 16 and re-run. There will be a sweet spot for both speed timings. It may be 3200 @ 17-20-20-42 or similar. You will see the latency come down as they tighten too. Need to try a bit at time. Those four timings are the ones to adjust slightly. Then write it down and test. If its too far the system may not boot into windows so you need to re-adjust in bios. Cheers.
 
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cheekykid

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KingLoki said:
The read and write speeds on the 3200 look good. Very close to 3600mhz. I would play a bit with the timings, very lightly and re-run tests. Drop the top timing of 18, down to 17 and run test. If no problems then try 16 and re-run. There will be a sweet spot for both speed timings. It may be 3200 @ 17-20-20-42 or similar. You will see the latency come down as they tighten too. Need to try a bit at time. Those four timings are the ones to adjust slightly. Then write it down and test. If its too far the system may not boot into windows so you need to re-adjust in bios. Cheers.
Click to expand...

I change it to 17 but when am back in windows and I check with cpu-z it still says 18 ? When I go back into BIOS to check it is still set at 17.
 
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cheekykid

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KingLoki

KingLoki

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cheekykid

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One clarification. Does XMP need to be disabled for the timing changes to stick? I currently have it at 17 but none of these programs actually indicate it. They all show 18.
 
JohnBonhamsGhost

JohnBonhamsGhost

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cheekykid said:
Does XMP need to be disabled for the timing changes to stick?
Click to expand...
as long as the XMP profile is enabled it will continue to load those settings upon boot.
but, when manually altering the RAM settings in the BIOS it should auto-disable the built-in profile.

when you alter the settings yourself make sure to save those settings inside the BIOS.
and maybe afterwards check to see if the XMP profile is still enabled before you exit the BIOS.
 
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