Dimar - Is it being fed whatever the spec'd voltage is for that speed, ad set up for all timings correctly? (Notice the Gskill featured 6400 MHz kit requires 1.4 V at it's advertised speed/timings...)
As intel's 'official' DDR5 spec is but 4800 MHz, we certainly can't count on their assistance until such speeds become 'standard', and, how long did it take for DDR4 to go from 2133 to 3200 MHz, and, even then, only on certain models? (the 11900K officially supported 3200 MHz, w/ the 10900k only w/2933 MHz speeds...); it could be years before we see 6400 MHz as any standard supported DDR5 speed
That's correct. You need a combination of a CPU with a good IMC and a capable motherboard. When it comes to the latter, the chances of hitting the higher DDR5 speeds with two-DIMM motherboards are higher.