Question Enabling XMP slows down post considerably

[Ankhseramun]

Hey hey people,
I've seen a bunch of threads considering problems with enabling XMP profiles, but none that are similar to mine.
As the title says, as soon as I enable the only XMP-profile provided by my RAM the time to post increases considerably.
It goes from 2-3 seconds to 30-40 seconds.
After posting everything runs completely normal but I have a feeling the time to post increases slightly with each boot.
I tried setting the timings manually but then the BIOS config is unstable and it forces me to reload default settings, this is probably caused by other settings I changed though.

Relevant parts:

• 4x8GB DDR4 G-Skill Ripjaws 3200MHz 16-18-18-38;
• i5-12600K;
• Gigabyte Z690 UD DDR4.

Could the culprit be the fact that two sticks were bought in 2018 and have Hynix chips while the other two sticks are from 2023 with chips from Samsung (clock and timings are identical)?

Cheers and have a great weekend!

 

[jojesa]

Could the culprit be the fact that two sticks were bought in 2018 and have Hynix chips while the other two sticks are from 2023 with chips from Samsung (clock and timings are identical)?

Cheers and have a great weekend!

I think you found the issue.

Mixing RAM running in dual channel , even if you use similar models, is not recommended.
It is hard to predict the outcome when you mix and match modules that were not tested to work together.
Besides appearing to have the same exact specification, the RAM that goes into a RAM kit (package) has been tested to work together.
RAM modules, even if they look similar, and have the same model they could have different IC chips brands, with internal timings that differ.

RAM has 3 timings categories and the only one we usually see is the "Primary"...the one in the packaging (e.g. 16-18-18-38 ).
But there are also a"Secondary" timings found on the 'SPD' section that could be available the BIOS (tWR, tRFC, tRDD_L, tRDD_S, tWTR_L, tWTR_S, tRTP, tFAW, and tCWL).
The "Tertiary" timings allows are nowhere to be found and we won't be able to control them.
Sometimes those timings could play nicely with one another and some other times they could even refuse to work together.

 

[Ankhseramun]

I think you found the issue.

Mixing RAM running in dual channel , even if you use similar models, is not recommended.
It is hard to predict the outcome when you mix and match modules that were not tested to work together.
Besides appearing to have the same exact specification, the RAM that goes into a RAM kit (package) has been tested to work together.
RAM modules, even if they look similar, and have the same model they could have different IC chips brands, with internal timings that differ.

RAM has 3 timings categories and the only one we usually see is the "Primary"...the one in the packaging (e.g. 16-18-18-38 ).
But there are also a"Secondary" timings found on the 'SPD' section that could be available the BIOS (tWR, tRFC, tRDD_L, tRDD_S, tWTR_L, tWTR_S, tRTP, tFAW, and tCWL).
The "Tertiary" timings allows are nowhere to be found and we won't be able to control them.
Sometimes those timings could play nicely with one another and some other times they could even refuse to work together.

Thanks for the fast reply!
As soon as I posted this I tested the sticks separately and it all worked perfectly.
Then I put all 4 sticks back in forgetting to turn off the XMP profile and the PC booted nigh instantly.
Now I have literally zero clue what is going on. I think I'm just gonna get me a new set next month just to be sure.

 

[SkyNetRising]

Then I put all 4 sticks back in forgetting to turn off the XMP profile and the PC booted nigh instantly.
Now I have literally zero clue what is going on.

Can you show screenshots from CPU-Z - memory and spd sections?
(upload to imgur.com and post link)

 

[Ankhseramun]

Can you show screenshots from CPU-Z - memory and spd sections?
(upload to imgur.com and post link)

Sure thing, there you go:

https://imgur.com/a/qR0rBNf

View: https://imgur.com/a/qR0rBNf

 

[SkyNetRising]

Show CPU-Z - spd section for all 4 slots.
You have screenshot for slot #1 only.

 

[Ankhseramun]

Oh shoot, my bad.

https://imgur.com/a/N9LGwi2

View: https://imgur.com/a/N9LGwi2

 

[SkyNetRising]

Looks good.
All modules have identical timing profiles.
You just have to make sure

Command Rate is set to 2T and​

DDR voltage to 1.35V.​

​

With a new kit 2x16GB you could set Command rate to 1T. Would be slightly faster.
But I doubt you'd notice any difference.

 

[Ankhseramun]

That's good to hear, thanks for helping out.
Another question came up:
I already tried changing the voltage to 1.35V in BIOS but wierdly enough it didn't let me change it.
As to the Command Rate, I've read up what it is and how it affects stuff but have no clue nor could I find anything on changing it.
Would you mind explaining it a little bit?

 

[SkyNetRising]

I already tried changing the voltage to 1.35V in BIOS but wierdly enough it didn't let me change it.

Probably did something wrong.
If you could show some screenshots, that might help.

As to the Command Rate, I've read up what it is and how it affects stuff but have no clue nor could I find anything on changing it.
Would you mind explaining it a little bit?

There's not much to explain. This can be found in advanced DRAM settings.
With 2 modules use command rate 1T.
With 4 modules, to remain stable, you have to switch to 2T command rate.