Memory issues with B650M PG Riptide

I recently upgraded to AM5 and threw in the B650M PG Riptide with 2x16 GB of 6000 MHz G.SKILL Trident Z5 Neo RGB, which feature EXPO.

Now, the thing is, if I choose the EXPO profile, the motherboard fails to POST.
The moment I save and exit, upon trying to boot up it will just stay there on a black screen. Eventually, after a couple minutes, the whole thing will shut down, RGB lights on the motherboard go off, fans stop. Then it tries again. Same thing, black screen.

This will happen three times. The third one it will boot up, skipping the POST altogether, and going straight into Windows, which will run the auto driver installer, indicating the BIOS was reset, and sure enough, the memory is back at 4800 MHz.
Any ideas if there's anything I can do to get them to work?

Also, Windows reports 32376 MB of RAM instead of the 32768 that it should (392 MB missing). This is having selected "iGPU Disabled" under "AMD CBS\NBIO Common Options\GFX Configuration" in the UEFI setup. With the iGPU enabled it's 31684 MB.

Is this normal?

Thanks in advance.

At some point I remember trying that, but I'll give it another go and report back.
Thanks!

what if you downclock the memory after you set the EXPO profile? like to 5600 or 5800mhz

Edited by M440 - 13 Mar 2024 at 3:50am