Maybe not the best place to ask but since somewhat related may aswell.
I've slowly been pulled into getting a DDR5 setup but the only thing stopping me is the immaturity of the platform. I do think that if you are getting a DDR5 setup to make sure you can push the frequencies required in the future, you would need a 2 DIMM board. However if you look at the Z690 Hero (4 DIMM) it has a QVL for 6800C40. The Apex board (2 DIMM) only has 6400C40.
Your results seem to show that 6800C40 would be more than capable on the Apex so why does Asus not list it? Does anyone know of any resources where someone tested a memory kit on both a 4 DIMM vs 2 DIMM to see what the differences were (same manufacturer obv)? I don't mind spending for the Apex if it's going to not hold back memory oc (or even in say 6 months handle some XMP 7,000 kits) but it would feel really bad if when Raptor Lake releases that the board manufacturers improved the designs so much that 4 DIMM budget boards in say the sub £200 range (B670?) are outperforming the £500+ 2 DIMM Apex.
For 99% of us, it's exactly the same as DDR4. Those chasing world records, or pushing for max benchmark results as a hobby with exotic cooling, will get the 2 DIMM boards (Apex etc). They'll also throw it away and upgrade to Z790 and AM5 when they release etc etc.
4 DIMM board are fine, as referenced by the QVL you mentioned. There are tens of thousands using Z690 4 DIMM DDR5 boards with XMP kits from 5200Mhz to 6400Mhz, vast majority without issue.
There's always the odd special person who'll try to run TWO 2x16GB XMP kits in a 4 DIMM board, then cry on forums when it doesn't work, this won't change. These folk need to settle for 4800Mhz JEDEC or wait for QVL 4 DIMM 64/128GB kits to be released.
