Question Z390 + 4133 RAM @ 3600 :(

[Gintama69]

Hi I have 9900K, Gigabyte Z390 Aorus Elite motherboard and 32GB(4x 8GB) G.Skill Trident Z RGB 4133 C19 RAM(2x F4-4133C19D-16GTZR).

Problem is I can't boot with XMP enabled(4133 C19), and also can't boot at 4000, but I can boot at 3800.

I'm running 3600 C14 1.40v manually atm. (tried 3800 C15 1.40v but wasn't successful)

• How much slower is 3600 C14 compared to 4133 C19?
• Should I try 3800 C16 1.40v or 3800 C15 1.45v?
• Any suggestions on improving RAM speed/performance?

____

p.s. I bought the RAM second hand, previous owner was able to run XMP settings without any issue on two different setup(X299 & Z390).
He was also able to run 4000 CL15 1.45v on X299(Asus Maximus XI Hero) and 4400 CL18 1.45v on 9700K, Asus Z390 Strix E motherboard.

So I'm not sure why I can't run 4000-4133+ on my setup..

• CPU's IMC
• low-end Gigabyte Z390 motherboard
• RAM itself

 

[matua2]

does 3866mhz work

 

[Gintama69]

does 3866mhz work

Not 100% sure tbh..
Because RAM speed setting in BIOS seems bit buggy(?) and sometimes RAM speed doesn't match the BIOS settings, e.g.

• once I got 3833 by setting RAM to 4000 in BIOS.
• other time I got 3200 in Win10 by setting RAM to 3600 in BIOS.
• think I was able to load into Win10 once with RAM set to 4000 and was actually running 4000, but I think it crashed iirc.
• another weird thing is as soon I enable the XMP, memory voltage become 1.40v automatically all the time even at 2133, but it's rated to run 4133 C19 1.35v.

I'm not sure why I'm having these issues, could be the faulty RAM? i.e. they became slightly faulty cos previous owner pushed it too much at 1.45v all the time etc?
Or is it due to low-end Gigabyte Z390 mobo or CPU's IMC etc?

I would just replace motherboard with better one if there's 100% guarantee that I can run at XMP or higher.. but not sure atm.