Cannot run 64GB (4x16GB) G.Skill Ripjaw RAM on default speed on Z390-E

Woeters · February 22

Hi guys,

So I just bought a set of G.Skill Ripjaws V 64GB (4x16GB) DDR4 3600 C18 F4-3600C18Q-64GVK to run on my ASUS ROG Z390-E, but it will not run on the default 3600MHz @1.35V.

I've tried XMP 1 and 2 settings, but it will simply run the 'MemOK' loop until it cannot find a suitable profile and return to UEFI. The maximum speed I can achieve is only 3400MHz, on which it runs stable during stress and benchmark tests. Because I thought there was something wrong with the memory set, I received a replacement set which does the exact same thing, so it's not due to faulty memory.

After mixing and matching different banks, I come to the following conclusion. Using only 2 banks (2x16GB in any configuration) it runs perfectly fine even at 3800MHz. As soon as I use 3 or 4 banks in any configuration, 3400MHz is the limit, regardless of XMP settings or Voltages. At 3466MHz with RAM at 1,45V it can get past the initial boot, but will cause an instant blue screen even before logging into Windows.

Increasing VCCIO and/or system agent voltages up to 1,4V had no results. Turning off MemOK on the motherboard results in the yellow DRAM LED to light up seizing the boot sequence.

Any ideas what may cause this issue?

Shimejii · February 22

Yeah, 4 dimms dont work at XMP. Pretty much been a thing for over a decade. Filling it out all the ram slots and attempting fast ram usually goes quite poorly. Im honestly surprised you even got 3400mhz to run, Often it doesnt go beyond 3000, usually 2666.

Zando_ · February 22

27 minutes ago, Shimejii said:

Filling it out all the ram slots and attempting fast ram usually goes quite poorly.

^^ Max DIMMs per channel + high density + high speed = really hard on the IMC, not guaranteed to run it successfully. I'd just keep it at 3400 and tighten up the timings as much as possible if you're worried about performance. Realistically it won't make much difference, and if you're doing non-gaming tasks then stability is king, so it's likely best to leave the timings stock and just pull the speed down to 3400.