Having issues getting 4 sticks of ddr 5 to run at 7800

[Phunction]

Hi, I have a system MAXIMUS Z790 DARK HERO - i9-14900K - G.SKILL Trident Z5 XMP 3.0 DDR5.

The Memory is 2 kits of 32GB, for a total of 64GB (4 x 16GB)

If I use just 2 and set the AI to XMP 2, it will boot fine and memory will run at 7800. However I am unable to get it to work with all 4 sticks.

The system will not post until I shut it down and go back into safe mode. Setting the AI to auto it will boot but ram will only be at 4000

Not sure what setting I need to change to get it to work with all 4? Even if I can get it to run at 7200 that would be OK.

I appreciate any pointers.

[Nate152]

Hello Phunction

Your memory is unstable because you're combining two memory kits. 

You will have to settle for a lower frequency or return a memory kit.

[Phunction]

So even though both kits are the same, it still will have issues?

[Nate152 · Accepted solution]

Yes, you will have issues because there is no such memory kit as 64GB 7800MHz, this has not been tested or validated. When combining memory kits, it throws everything off including X.M.P.

You can still use it, manual tuning of the frequency, timings and voltages is the way to go, but you won't get close to 7800MHz. 

If your pc is primarily for gaming, I would opt to keep 32GB 7800MHz as speed is king for gaming.

[Phunction]

Ok, thanks.

Looks like the fastest 64GB set I can find is 6800 or 6400, the 6800 is about $50 more, is it worth it?