2 32g kits. When I bought it, I didn't know that it was better to use only 2 slots. So I bought 2 kits with a frequency of 7800, as a result, I managed to make them work stably only at 6400 and I resigned myself to it.
I have the same problem after updating the BIOS. Before that, my RAM worked at 6400 on the XMP 2 profile, now it is stable only 6000 on XMP 1. 4x16 RAM are installed.