I've been meaning to make this thread for a while, which is with regards to memory overclocking on the Rampage VI Extreme Omega. Basically, I have found it to be a bit of a pain getting 4000MHz stable, but I have managed it and with a few caveats. I've attached an image of my timings and system specs for reference, along with validation of stability.

So I had to actually manually tune the ODT values to get this stable, as the BIOS auto settings were not sufficient. The BIOS also does not show the ODT values under auto, so it required a lot of trial and error. It would be nice if the BIOS actually showed the values under auto, since I was told it can be useful applying values that the BIOS would automatically apply at lower memory frequencies.

The RTL/IOLs drift a little bit from one boot to another. Sometimes the RTLs are aligned 59-59-59-59, other times I'll get 59-59-61-59. Usually this is not an issue, although a few times I've had games crash randomly, then ran a memory stability test to get an error rather early. Other times, I can go 10,000%+ coverage in Ramest. And yes, I have confirmed stability through HCI and GSAT. Some boots are rock solid, others are not.

Another thing I noticed is that while conducting a few gaming benchmarks, I would get a complete system lock sometimes if my GPU OC was unstable for a run. Normally the application should crash and I should not have to shut down the system. With my 3800 CL15 profile, this is not the case at all, as only the application crashes. So there is certainly some instability with my memory, despite passing all of these stress tests on "most boots."

I was talking with a few folks in a Discord and they seem to think it's really an issue with the BIOS. I know a lot of people who have had trouble with 4000+MHz on this board and the original Extreme, yet they could manage 3800 CL14/CL15 without issue. Those I have spoken with who have the issues also have the Trident Z RGB kits, which have a different PCB than the non-RGB kits. So there may be an issue there, although I really do think some of the BIOS auto settings could be to blame at 4000MHz or beyond. I manually tune all primary, secondary, and tertiary timings. The fact that I had to tune the ODT values seems to be an indicator that perhaps the BIOS is settings those incorrectly in my case.

On a last note, I can't even boot at 4200MHz, regardless of voltages and regardless of how much I loosen the timings. Considering I can boot this kit at 4000 CL17 at 1.35V, this seems a bit strange. Again, maybe the BIOS doesn't know what to do with this particular kit (Trident Z RGB 3600 CL16)?

I just felt like sharing my experiences with this board regarding memory overclocking. I am also hoping that some of these less common settings to tweak (like ODT values) are set more accordingly with auto with future BIOS updates, although I don't think it's likely given that this is a board not many people own and not a priority by Asus.