9900KS & Maximus XI Extreme & RAM OC = kills Memory Write

[Mappi75]

Hi

replaced my 9900K with the 9900KS did a Bios reset and a Bios Flashback with the same bios,
because this combo shows a strange behavior.

Every time i want to run the memory with 4000+ Mhz (32GB G.Skill 4.133 17-17-37 Kit),
the Mobo did sometimes boot twice and then it loads win 10.

But then the Memory write is like 40-50% less as it should be:



When this happens there no way to get the normal speed back (only Bios Flashback will work)!

Here is a pic how it should work:



Does somebody else have the problem too?

[Mappi75]

Ok it looks its only when i try to set the 4.133mhz for the memory.

This time the Board did not boot twice..

[edrickjk]

Try the second bios, keep in mind your memory controller in on the cpu and it might not like higher frequency,or might need more voltage . When you will find an acceptable setting for your ram,turn off the memok it will prevent the board to constantly retrain the memory.

[Mappi75]

Update:

the memory will work only with max 3.600Mhz - over 3.600Mhz the system will reboot often and MemOk! will reduce the memory speed 100mhz less.

The strange:

After MemOk does its job it will reduce every time the RAM voltage from 1,45v or 1,4v to 1,35v (1,35v every time)

Even when i set the memory to 3.800mhz it will set the ram voltage to 1,35v !?

Another experience:

i tried to use 3.600mhz cl16 and the reboot hang and in bios i saw the he uses 3.600mhz cl15 - never changed any setting to cl 15 !


I switched from Bios1 to Bios2 / i reset the bios / i make serveral time a bios flashback but nothing helped here.

I removed carefully cpu and the ram and set it new into the system.

Before using the 9900KS i used a 9900K which runs perfect with 3.900 Mhz 17-17-37.
Never run into a memok! boot loop which the KS does.

[edrickjk]

They binned the cpu for frequency not for the memory controler, you might have lost the silicon lotery. I would write down your stock memory setting and set them manually without xmp ,you will need to adjust your vccio and vccsa manually accordingly. On the other hand if your ram work good at 3600, i would consider leaving it there and just lower your timing.

[Mappi75]

I found the solution:

- tWRWR_dg was "8" and have to be "4" (thats fixes the bad WRITE performance).
- disable MemOk! on Mobo
- loading XMP II Profile and set the voltages higher

> the system boots without problems



Before the KS i used only XMP I Profile - dont know why this time only XMP II will work.

[Silent Scone@ROG]

I found the solution:

- tWRWR_dg was "8" and have to be "4" (thats fixes the bad WRITE performance).
- disable MemOk! on Mobo
- loading XMP II Profile and set the voltages higher

> the system boots without problems



Before the KS i used only XMP I Profile - dont know why this time only XMP II will work.

XMP II is the memory vendor profile, which tends to have looser sub timings than the optimised board profile (XMP1). Your new CPU likely has a slightly weaker IMC.

[cniedzi]

I found the solution:

- tWRWR_dg was "8" and have to be "4" (thats fixes the bad WRITE performance).
- disable MemOk! on Mobo
- loading XMP II Profile and set the voltages higher

> the system boots without problems



Before the KS i used only XMP I Profile - dont know why this time only XMP II will work.

I had the same write bandwith issue with MXIH and my RAM overclocked over 4000 MHz. In Mode 2 memory training sets incorrect tWRWR_dg value (even in XMP I). In Mode 1 it is set ok, but in Mode 1 I get WinRAR CRC errors even when using RAM rated speed (3866 MHz).

I also had random MemOK! when using rated RAM speed &3866 MHz. Playing with VCCIO and VCCSA and VRAM doesn't prevent from random MemOK! What I've done was to set MRC Fast Boot to enable and Fast Boot after AC Power Lost after successful first memory training.

[Mappi75]

Did you set the SA + vccio boot voltage ?

In bios you can set higher voltages for booting the system - and then it will take the normal voltages.

[cniedzi]

Did you set the SA + vccio boot voltage ?

In bios you can set higher voltages for booting the system - and then it will take the normal voltages.

It doesn't work for me