ROG Strix Z790-F Wi-Fi (I): stabilizing 128GB at 5600MHz

[Hari_Seldon]

I would like to stabilize (pass all relevant MemTest86 tests) on my system with 128GB at 5600MHz.  Basics of system:

• ROG Strix Z790-F Wi-Fi (model I)  (BIOS 1801)
• Intel i7-14700K
• Kingston KF556C40BWK4-128
• Seasonic Focus V3 GX-1000
• No OS currently installed (this is after the hardware is working)

While I am able to *mostly* get it to pass at 5400MHz, I would like it to pass at the 5600MHz (XMP Profile #1).  For 5400MHz, I select XMP I at 5200MHz then change the frequency to 5400MHz.  It passes every test except Test #13 (Hammer test).  There are many tweaks I can do, but I rather follow the KISS principle, which matches me.  😀

When I select the 5600MHz profile, it fails sometimes on tests #7 (Moving inversions, 32 bit pattern) and #9 (Modulo 20, Random pattern) and nearly all the time on test #8 (Random number sequence).  Hence, I have been testing against Test #8 prior to running longer sets of tests.

I understand that this memory is not quite on the QVL for the motherboard, but it should be basically the KF556C40BWAK4-128 without the RGB.

Questions:

• How valid is the Hammer test?  It is not enabled by default in the board's MemTest86, so I have to wonder why.  It could be because it is a very long test.  I will be downloading the v10.6 of MemTest86 for future tests since it claims to run the Hammer test faster now.  It does seem important according to information about that test:
  • https://www.memtest86.com/tech_individual-test-descr.html
  • https://www.memtest86.com/troubleshooting.htm#hammer
• Has anyone here gotten 128GB at 5600MHz to work?  I assume ASUS has since they have 128GB kits on the QVL.
• Is this a potential issue with the memory?  I can still return it to Amazon and try with a new kit.
• If not returning the memory, should I go through ASUS or Kingston support first?

Thank you!

Update:  Running MemTest86 v10.0.6 with the RAM at 4800MHz has passed all the tests twice.  The newer version of MemTest86 gives more details such as RAM temperature.  4800MHz is not exactly ideal, but I think it says that the memory itself is not absolutely bad.

[Dragonfly79887]

Up to now, it is very difficult to run stably at the highest ddr5 speed with 4 ddr5 bars. My system: 14900K, Z790 Dark Hero. I have 2 cosair 2x 32 kits (DDR5 6000MT/s CL30 ( Total 128 gb ddr 5 ) I cannot run XMP . My computer cannot turn on . I tried setting the bios to default. - Who Overclock tuner : AUTO - DRAM Frequency : 5600 My system seems to run fine and haven't had any problems in 2 days. Then I tried using memtest86 to test at that speed and got 779 errors

 Then because I wanted to experience it, I decided to upgrade my DDR5 to: 2 Kit x ​​96GB - Ram PC Corsair Dominator Titanium 96GB 6600MHz DDR5 (2x48GB) CMP96GX5M2B6600C32 (Total: 192 GB) I can only reach 5600 with manual adjustment like that. I can't use XMP even though my DDR supports speed 6000. I was told by friends on this forum that 4 DDR bars cannot be OCed. It cannot run at great speed. If you want to OC to great speeds, just use 1 kit (2 ddr5 sticks).

The 14900K doesn't even like 4 sticks of DDR5. That's what I learned on the forum.

[Hari_Seldon]

Thank you for that information.  I had read here and other sources that it can be difficult to overclock 4 sticks, but I typically see people saying that for trying to run faster than the XMP profiles or when mixing kits.  A few places said they could run this 4-stick kit at the 5600MHz profile which got my hope up that I could too.

The question in my head now is how did ASUS accomplish 5600MHz?  The QVL shows both RAM speed and supported speed of 5600MHz.  How seriously should the QVL be used?  Would it be better to buy 2 2x32 kits rated at higher speeds and shoot for a lower speed (i.e., 5600)?

As this system is multi-purpose (software development, builds, VMs, games), I would like the extra memory but greedily want the speed too.  I wish there was a 2-stick kit for 128GB+.

[Dragonfly79887]

Although my Z790 Dark Hero can support 4 sticks of DDR5, it is difficult for OC. Maybe we need to wait for a new BIOS version for it to be able to do that. Yes, in a situation like this, a ddr5 kit with 2x 64 bus 8000 is probably something we all desire. About my system : Z790 dark hero 14900k and my DDR5 to: 2 Kit x ​​96GB - Ram PC Corsair Dominator Titanium 96GB 6600MHz DDR5 (2x48GB) CMP96GX5M2B6600C32 (Total: 192 GB). To run at speed 5600, I have to do almost nothing except: In BIOS DRAM FREQUENCE : => I set bus dram 5600. Then reset pc and DONE. I tried with 6000 but couldn't turn on the computer

[Dragonfly79887]

Thank you for the information. Currently I am using the latest memtest86 ver 10.6 build 3000 and test kit ddr5 192 Gb at speed 5200. I've been testing it for a few hours now and I'm not at home right now. When I have the results, I will notify you so you can have more experiences. Regarding what I want at this time, after listening to the advice of the brothers on the forum: Do not use 4 ddr5 bars for this board or other advice is that 14900k does not like 4 ddr5 bars. I'm just looking for the most reasonable and stable clock speed. The clock level can be 5000 , 5200 or something .

[Vynra · Accepted solution]

if you get a single error in any ram test that is a extremely bad sign. memtest86 is a good test just to test for any significant issues. if your failing that then you got major issues that can corrupt your OS and even have crashes.  you never want to mix kits. ever. and that is a lot of ram for that speed. if your failing at 5400 there is absolutely no way to do 5600 unless a bios update allows that. sorry but you need to just lower the speed to where you do not get a single error. also need to test stability.

[Dragonfly79887]

Thank you for the instructions. I'm new to learning and practicing OC so I don't have much experience. I really need guidance like this and I appreciate it. So now I should set speed 5600 and run memtest86 ( newest 10.6 when dram speed 5600 ). If it has 0 errors, should I run at this speed level? If not, should I reduce the dram bus?

[Dragonfly79887]

Thank you guys for the useful information. Because I bought 4 ddr5 bars, I decided to run at the default ddr5 clock speed of 4800. After listening to the advice and instructions of the guys on the forum, I understood the OC with 4 ddr5 bars on one. PC is difficult. And inherently the 14900K doesn't like 4 bars. I decided to run 4 ddr5 sticks at the default clock of 4800 to stabilize the system and not harm the dram. Thank you.

[Hari_Seldon]

I would choose MemTest86 v10.0.6 over the installed one.  Here is the changelog since 10.0.0:  https://www.memtest86.com/whats-new.html  There are several fixes for Raptor Lake, which probably apply to Raptor Lake Refresh.  The one thing that threw me off is that the current voltage shown is the default voltage of 1100mV even if 1250mV is what is actually set.  Showing the temperature of the memory instead of N/A is a bonus for me.

I am probably going to stay with 4800MHz choosing size over speed even though 2x48 is tempting.  4800MHz is still much faster than hitting swap.  5000MHz seems to work, but I get the warning about the memory "may be vulnerable" to Hammer row bit flips.  No errors, but 4800MHz does not give me that warning.  The next step will be to run some stress tests on the system.  Since it will be FreeBSD (UNIX-based system), I will be running some tools listed for Arch Linux:  https://wiki.archlinux.org/title/Stress_testing

It is unfortunate that there is not a simple way to tweak the memory closer to what the QVL claims.  All the Kingston 4x32 kits in the QVL claim to handle 5200MHz+ for my board.

[Dragonfly79887]

I set it to 5200 and ran memtest86 but it still seemed like there were a few small errors. In the end I decided to run 4 ddr5 bars at the default clock of 4800. High speed is an interesting thing but perhaps stability is still important .