F4-3200C14Q-64GTZ - 64GB, CL14 XMP settings cause flickering screen

[Fred]

Hi,

I have a set of F4-3200C14Q-64GTZ (4x16) Gskill memory installed.

Unfortunately, when I enable XMP and boot to windows, the screen flickers on and off.

Processor 6700K (stock)
Memory: F4-3200C14Q-64GTZ (4x16) at XMP
GPU (integrated 6700K)
SSD - S950 Pro
Motherboard Asus Z170-Premium (bios 1803, latest)

That's it in the system at the moment.

The monitor is a P279Q via HDMI.


Any help is appreciated.

[emissary42]

You probably have to manually adjust/lower VCCSA (and VCCIO) to stop the flickering. I had similar issues with my own Skylake setup using the iGFX from a certain memory clock upwards, because the MB went way overboard with those voltages if they were left on auto.

[Fred]

I've tried that some.

MB gives:

VccIO 1.100V
VDDR 1.344V
VccSA 1.184V

I have tried kicking VDDR up until it measures 1.35V.
I have tried moving VccIO and VccSA up and down by about 100mV to no avail.

[emissary42]

Adjusting it a certain amount by guessing might not work, i had to find the actual sweet spot for them. And from my experience Vdimm does not affect this at all, since i had no issues with very low or very high values for it, as long as the other voltages were right on spot.

(ASUS ROG Maximus VIII Gene)

[Fred]

I've not been able to find a solution.

It also causes the Asus board to always end with a 6F Q-Code (could be bF)

[emissary42]

If you don't want to invest the time to fix the voltages, then lower the memory ratio.

From my testing with kits from different manufacturers, this is not memory specific but a "feature" of the mainboard and happens from a certain memory ratio upwards, unless the mentioned voltages are manually adjusted.

6F = System Agent DXE initialization
B6 = clean up NVRAM

So both codes are somewhat related to the iGFX and system agent (voltage). Maybe contact the ASUS support for more help.

[Fred]

I've been keeping them together, going 1.0V to 1.25V on VccSA and VccIO in 25mV steps.
I'm hesitant to take them much higher than 1.25V

I guess I can try sweeping VccSA at VccIO's of 1.0V, 1.1V and 1.25V and see if I find a combo that works.

[emissary42]

No need to go upwards, just try decreasing both in small steps from the AUTO values.