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

Level 8

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.


  • 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:
  • 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.


Level 8

I also decided to stick with the 128GB at 4800MHz for the stability.  With over 20 passes using memtest without a single error, I am pleased.  96GB (2x48) was an option, but quantity is more important for my use cases on this system.  Still, there is hope some stability will come with newer BIOS updates.

The next step is undervolting this CPU, if possible, but that is a topic for another thread.