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DDR5 Memory won't go past 4000mhz to reach 4800mhz on Z690-F

Kravena
Level 7
Just put together a Z690-F (Bios 0702), 12900k and 4 x 8gb Crucial ( CT2K8G48C40U5 ).

Memory isn't listed on the QVL, just to get that out of the way.

It all works, but if I set the MB to XMP I to enable 4800mhz, the motherboard will not post. When it does eventually boot, the memory drops to 4000mhz and not the 4800mhz on the XMP I.

Anyone else getting similar issues ?
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xeromist
Moderator
4 sticks is often harder to run and given that it's not on the QVL it's going to be hard to know if you just have a weaker CPU or if there is a real compatibility issue. I would try choosing some speeds between 4000 and 4800 to see what will post, then run some memory tests to verify stability. You might be able to get relatively close to the advertised speed with some tweaking. If you are attached to this memory kit it's possible that future BIOS updates may improve stability at higher speeds (since the platform is new) but there are no guarantees.
A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station…

kusax01
Level 8
Kravena wrote:
Just put together a Z690-F (Bios 0702), 12900k and 4 x 8gb Crucial ( CT2K8G48C40U5 ).

Memory isn't listed on the QVL, just to get that out of the way.

It all works, but if I set the MB to XMP I to enable 4800mhz, the motherboard will not post. When it does eventually boot, the memory drops to 4000mhz and not the 4800mhz on the XMP I.

Anyone else getting similar issues ?


Check the last post from Shamino in this thread:

https://rog.asus.com/forum/showthread.php?126369-Maximus-Z690-and-Alder-Lake-Modern-CPU%92s-require-...

I had a similar issue, when i used my XMP profile my PC wasn't booting. With this new BIOS version published by Shamino, i was able to fix it, and now my PC is running at 5200 Mhz....

Silent_Scone
Super Moderator
Kravena wrote:
Just put together a Z690-F (Bios 0702), 12900k and 4 x 8gb Crucial ( CT2K8G48C40U5 ).

Memory isn't listed on the QVL, just to get that out of the way.

It all works, but if I set the MB to XMP I to enable 4800mhz, the motherboard will not post. When it does eventually boot, the memory drops to 4000mhz and not the 4800mhz on the XMP I.

Anyone else getting similar issues ?



Hello,

Update to the latest UEFI as instructed. However, that is a two DIMM memory kit. If needing to ask these questions, one should refrain from mixing memory kits.

https://rog.asus.com/forum/showthread.php?57038-Don%E2%80%99t-combine-memory-kits!-The-meat-and-pota...
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Same issue, I'm using Crucial 16GB sticks of DDR-4800mhz and I can't get past 4400mhz when I use 2 sticks.

Specifically, I have 2 sticks of:

Crucial by Micron
CT16G48C40U6.M8A1 16GB DDR5-4800 UDIMM 1.1V CL40

Which IS on the QVL memory list for the board so it should be officially supported. However it refuses to run at 4800mhz (the computer won't boot up if an XMP profile is enabled) however it does boot at 4000mhz and 4400mhz.

I applied the latest 08 bios released Nov 15th and it didn't help.

I'm using the Hero Z690 and a 12900k.

I keep on testing the latest BIOS (0802) and unfortunately none of these are helping the issue.

Are there planned fixes within the BIOS updates or perhaps I should look into replacing the memory? (Mind you, DDR5 is impossible to find/buy now)

kaybee123 wrote:
Specifically, I have 2 sticks of:

Crucial by Micron
CT16G48C40U6.M8A1 16GB DDR5-4800 UDIMM 1.1V CL40

Which IS on the QVL memory list for the board so it should be officially supported. However it refuses to run at 4800mhz (the computer won't boot up if an XMP profile is enabled) however it does boot at 4000mhz and 4400mhz.

I applied the latest 08 bios released Nov 15th and it didn't help.

I'm using the Hero Z690 and a 12900k.


Hello,

Try increasing VDD and VDDQ to 1.25v
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

After trying just about everything else, I got my memory to read at 4800mhz by installing the latest bios, setting XMP2, switching the two dimm slots, and setting voltages to 1.25. Is that a safe voltage for my Crucial 64GB (2 x 32GB) 288-Pin DDR5 SDRAM DDR5 4800 (PC5 38400) Desktop Memory Model CT2K32G48C40U5? It's advertised at 1.1V. I am a bit of a newbie, so I appreciate this thread and your help.

After trying just about everything else, I got my memory to read at 4800mhz by installing the latest bios, moving the RAM to two different slots (still with a slot between them), and setting the BIOS to XMP2.

If you haven't already tried swapping the RAM slots, might be worth a try. I really appreciate this thread and Shamino for posting the updated BIOS. Thanks for helping me solve this.