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z690 Apex with Samsung DDR5 Memory Issues?

Murlo26
Level 10
Hi,

I have a new build put together and the memory is giving me all sorts of issues. I have seen a few people saying that the Apex board might have some dim slot issues but not sure if that is actually an issue. I snagged up a 6000mhz CL36 G Skill kit and tried pairing with my apex board and 12900k. Everything is on a custom water loop with fairly solid temps. I am on the latest bios. I recognize the Samsung flavor of sticks are not officially supported by the Apex board yet, but am curious as to why (per the QVL). The hero board has mine listed already but the apex list seems light. I tried the XMP profile and have had very little luck. I have been able to get it to boot into windows but typically crashes on any heavy workload and sometimes even just being in windows things lock up.

I am just curious if this is something I need a bios update for and just have to wait or I should look at going after different memory. Part of why I got the apex was to finally play around with memory overclocking but not even being able to run xmp kind of sucks. Just surprised that the apex board has so little support for memory so far.

Any thoughts?

I appreciate any help and sorry if this is covered elsewhere.

PC Components:

12900k (stock for now until I get memory sorted)
z690 Apex
G Skill F5-6000U3636E16GX2-TZ5K (32gb)
EVGA 3090 Kingpin Hydrocopper
EVGA 1300W G2 PSU
Corsair 5000d
2x360mm radiators
Windows 11

Edit: I have also tried the built in profiles on the apex, like all of them and none of those seem to work even speeds down to like 5200mhz, wouldn't boot into windows on those. I also tried the XMP and bumped voltage up...no luck really.
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139 REPLIES 139

Silent Scone@ROG wrote:
Enable Tweak Mode 2. (Extreme Tweaker>DRAM Timing Configuration).

Set MCVDD 1.3v

Enable MRC Fast Boot

Disable MRC Full Check

You can try XMP I first, if you like. This is the validated profile, although the sub timings will often be tighter than the default DIMM profile.


Did this along with TXVDDQ to 1.35.

Still failing Memtest, about half way through it is showing 14 errors. It also wasn't called MRC full check I think it was MHC full check or something like that, can't look right now as letting memtest go more...already up to 16 errors, so this seems more unstable.

Deke06
Level 7
According to the guide in the sticky, you should also change the Transmitter VDDQ voltage to the same voltage you set for VDD or VDDQ, whichever is higher.

If that doesn't work, try giving it more voltage at some point. It took 1.375 for me.

Dialing in a number for the System Agent Voltage did not work for me with this kit. Oddly, I had to set System Agent to Offset Mode, and the Offset was set to auto.

A fail is a fail, doesn't matter what you're testing with. I'd suggest testing with at least two different programs.

Murlo26
Level 10
Well spent a good chunk of time this afternoon trying all sorts of combinations of voltages...tried bumping up to 1.25 System agent voltage, seemed to help some, but ultimately still getting errors in memtest.

I assume to call something 24/7 stable for gaming and every day use I should be able to pass memtest without errors. So back to the drawing board...also bumped up to 1.4v on vdd and vddq and still nothing. I am starting to wonder if maybe some timings need to be loosened.

Murlo26 wrote:
Well spent a good chunk of time this afternoon trying all sorts of combinations of voltages...tried bumping up to 1.25 System agent voltage, seemed to help some, but ultimately still getting errors in memtest.

I assume to call something 24/7 stable for gaming and every day use I should be able to pass memtest without errors. So back to the drawing board...also bumped up to 1.4v on vdd and vddq and still nothing. I am starting to wonder if maybe some timings need to be loosened.


Passing Memtest86 is probably the easiest on the memory sub system so you need to pass this, yes. Try Tweak Mode 2 as suggested before tuning further.

Up to 1.4v on Memory Controller VDD may help, or it may not. These voltages don't always scale in a linear fashion, so tuning is the operative word and not simply increase in some instances.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ROG wrote:
Passing Memtest86 is probably the easiest on the memory sub system so you need to pass this, yes. Try Tweak Mode 2 as suggested before tuning further.

Up to 1.4v on Memory Controller VDD may help, or it may not. These voltages don't always scale in a linear fashion, so tuning is the operative word and not simply increase in some instances.


I tried this and no dice. Went up to 1.4 on mem controller and things just wouldn't work. I also tried tweak mode 2 as well. And the MCH full check too, no go.

I tried all sorts of combinations of up and down and just could never quite get it stable. I think the mem controller voltage liked being lower better. I also tried upping the frequency wondering if maybe it just didn't like 6000, nope even worse.

So finally I dropped frequency down to 5800 and everything worked and passed memtest first try. So then I starting putting voltages lower. Also, the XMP I seemed more stable for whatever reason than stock dim stuff, I was getting less errors so I stuck with it.

I am on these settings right now:

XMP I
5800
VDD 1.35v
VDDQ 1.35v
MCVDD 1.25v
CPU System Agent voltage 1.25v
TXVDDQ 1.35v

I put the other stuff back to default, like tweak mode, full check etc as well.

Memtest passed this 100% so going to try some other memory stability stuff, not sure what else to use but will find something.

So not sure if this is just these samsung sticks not being the best as I have read in many spots that the SK hynix ones seem to work better, more stable and clock higher. Or maybe just my CPU isn't the greatest. I dunno.

edit: just ran AIDA64 extreme stability test, just selected memory, ran just fine no issues for over an hour, guessing I am fairly stable now.

Murlo26 wrote:
I tried this and no dice. Went up to 1.4 on mem controller and things just wouldn't work. I also tried tweak mode 2 as well. And the MCH full check too, no go.

I tried all sorts of combinations of up and down and just could never quite get it stable. I think the mem controller voltage liked being lower better. I also tried upping the frequency wondering if maybe it just didn't like 6000, nope even worse.

So finally I dropped frequency down to 5800 and everything worked and passed memtest first try. So then I starting putting voltages lower. Also, the XMP I seemed more stable for whatever reason than stock dim stuff, I was getting less errors so I stuck with it.

I am on these settings right now:

XMP I
5800
VDD 1.35v
VDDQ 1.35v
MCVDD 1.25v
CPU System Agent voltage 1.25v
TXVDDQ 1.35v

I put the other stuff back to default, like tweak mode, full check etc as well.

Memtest passed this 100% so going to try some other memory stability stuff, not sure what else to use but will find something.

So not sure if this is just these samsung sticks not being the best as I have read in many spots that the SK hynix ones seem to work better, more stable and clock higher. Or maybe just my CPU isn't the greatest. I dunno.

edit: just ran AIDA64 extreme stability test, just selected memory, ran just fine no issues for over an hour, guessing I am fairly stable now.


Hynix is easier to work with for users who aren’t keen on manual tuning, but Samsung is just as good for these frequencies *You can also try the profiles that come loaded with the board. The Samsung profiles are tighter and 1T command rate, but may help stability.

Ultimately it’s often a multitude of things, some CPU may not like operating at 6K without too many concessions to latency. Finding a window for stability for a given CPU on this platform can require patience.*
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ROG wrote:
Hynix is easier to work with for users who aren’t keen on manual tuning, but Samsung is just as good for these frequencies *You can also try the profiles that come loaded with the board. The Samsung profiles are tighter and 1T command rate, but may help stability.

Ultimately it’s often a multitude of things, some CPU may not like operating at 6K without too many concessions to latency. Finding a window for stability for a given CPU on this platform can require patience.*


I did try the profiles before but those were not working well. But maybe I could try modifying one of those a bit. I find mind tuning, I have just never really done it so not sure what to try I guess. Maybe I’ll try some of the pre loaded profiles and tinker more with those. I’m just happy they seem stable where they are now as before I had to run at JEDEC. Any other stuff to try I’m willing. Or if there is a good guide out there I’m willing to read it. It just seemed like voltage wasn’t the issue at 6000, guessing I’d have to relax some timings or something.Â*

Silent_Scone
Super Moderator
These are my daily settings with that same memory kit on the Apex. Remember to save the CMO file in profiles for your current stable settings.

Please note active cooling may aid stability when pushing module voltages

UEFI 1101
C30-34-34-54 1T
VDD 1.45v
VDDQ 1.45v
VDDQTX [Auto]
MCVDD 1.25v
VCCSA 0.98v
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090

Silent Scone@ROG wrote:
These are my daily settings with that same memory kit on the Apex. Remember to save the CMO file in profiles for your current stable settings.

Please note active cooling may aid stability when pushing module voltages

UEFI 1101
C30-34-34-54 1T
VDD 1.45v
VDDQ 1.45v
VDDQTX [Auto]
MCVDD 1.25v
VCCSA 0.98v


I am on that same bios. Those are much tighter timings than I have, I will try something similar and see if it takes but not holding my breath. I am guessing that is at 6000 as well?

I am surprised your system voltage was able to stay that low, I feel like I had to go up to get it remotely stable. Seems like your kit is working well though so nice. Thanks for the help regardless. I will save my current settings in a daily profile and then keep tinkering. Still might go for an SK hynix kit anyway and sell this but we will see where I can get. Also probably going to start with some of the profiles built into the apex board and see if I can get any of those working.

You actually have the exact same memory kit? Or just similar samsung gskill one?

Murlo26 wrote:
I am on that same bios. Those are much tighter timings than I have, I will try something similar and see if it takes but not holding my breath. I am guessing that is at 6000 as well?

I am surprised your system voltage was able to stay that low, I feel like I had to go up to get it remotely stable. Seems like your kit is working well though so nice. Thanks for the help regardless. I will save my current settings in a daily profile and then keep tinkering. Still might go for an SK hynix kit anyway and sell this but we will see where I can get. Also probably going to start with some of the profiles built into the apex board and see if I can get any of those working.

You actually have the exact same memory kit? Or just similar samsung gskill one?


Same kit and frequency, more voltage.
13900KS / 8000 CAS36 / ROG APEX Z790 / ROG TUF RTX 4090