13900K + Z690 RAM Speed slower than Z790?

[Fatpizza]

With Raptor Lake I was under the impression that it was the memory controller on the CPU that dictated the RAM compatibility rather than motherboard?
For example I used to have my 13900K running an 8000Mhz GSkill 48GB kit in an ASUS Z790 Apex with absolutely no problems. But when putting the same RAM and the same CPU into a AsRock Z690 Aqua OC, I can't run it stable past 7000Mhz no matter what I do. I'm not really that fussed as the performance difference in reality is minimal, but it's still slightly annoying. Especially since the Aqua OC is supposed to be such a high end board.

 

[Fatpizza]

The motherboard as somthing to do with memory speed. Its literally on there site.
Anything passed the Intel memory supported speed 5600 is an OC and down to a lot of factors, the main one been the motherboard.


AsRock Z690 Aqua OC

• Supports DDR5 non-ECC, un-buffered memory up to 7000+(OC)*

ASUS Z790 Apex

• Supports DDR5 non-ECC, un-buffered memory up to 8000+

Intel ARK

• Memory Types Up to DDR5 5600 MT/s

Thanks. I had seen that, but I'd figured that may have been a holdover from when it was the first released with Alder Lake CPUs. And there are many reports that improved memory controller of Raptor Lake allows higher RAM speeds. But that is obviously still somewhat limted by the motherboard.
Plus I'd seen all these reports of overclockers getting DDR5 to run at 7960Mhz, but when looking closer that was with a single DIMM at absolutely horrible timings.

 

[Fatpizza]

When my RAM was set to 7200 I was able to run Cinebench with no issues for over half an hour, but as soon as I ran memtest86 errors started spewing out.
6933 ran memtest86 successfully once but had one error on the 4th pass on the 2nd attempt. 6800 was perfectly stable over multiple attempts.

That's with setting XMP and then just changing the frequency. Didn't touch the timings.

I'm OK with 6800. My main concern was that I'd done something wrong and would have to pull my PC apart to re-seat the CPU.