4000Mhz RAM only running with 2133 even though D.O.C.H is enabled

[Sanedish]

CPU: Ryzen 9 5950X

RAM: 32GB SKILL TridentZ RGB 400Mhz [4 Modules]

MoBo: Asus B550-E GAMING

 

[Eigenvektor]

Can you check with CPU-Z which XMP/DOCP profiles the RAM supports? Maybe you need to select a different one.

 

Four sticks is typically more difficult to get running, the higher the clock speed. Maybe try with two sticks first.

 

~edit: If memory serves, sweet spot for DDR4 on Zen 3 is 3777 MT/s. Beyond that, your infinity fabric will drop to 1:2, unless you overclock that as well (and limit is 1900 MHz, I think, i.e. 3800 MT/s). So 4000 MT/s might actually cost some performance compared to 3777 MT/s.

[RONOTHAN##]

12 minutes ago, Eigenvektor said:

If memory serves, sweet spot for DDR4 on Zen 3 is 3777 MT/s. Beyond that, your infinity fabric will drop to 1:2, unless you overclock that as well (and limit is 1900 MHz, I think, i.e. 3800 MT/s). So 4000 MHz might actually cost some performance compared to 3777 MT/s.

It depends on the board, most will automatically go to desynchronized mode when going above 3600MT/s. If you do manual overclocking, most chips will max out at 1900MHz FCLK, though there are a handful of really good chips that do 2000MHz, so 4000MT/s could technically be possible (it's very unlikely though, especially with the dual CCD chips like the 5900X)

 

33 minutes ago, Sanedish said:

MoBo: Asus B550-E GAMING

From everything I've seen, this board isn't great at overclocking dual rank memory, so odds are you'll top out at ~3800MT/s even if you are desynched from the FCLK. Ditch two DIMMs to see if there's a shot that you can run 4000MT/s in 1:1:1 mode, but odds are you'll need to lower the speed down to get this to work.