What will matter more than the Z690 or Z790 chipset is the overall feature-set and design of the board, as the only difference between the two chipsets is one is capable of more connectivity. But just because it is, doesn’t mean all Z790 boards will offer the connectivity the chipset is capable of and will in all likelihood use the name purely for marketing. So when looking up boards, look at the overall feature-set of the board and judge the price-value accordingly. For RAM OC, I again do not think the chipset matters, as a 2-DIMM Z690 APEX will likely edge out all 4-DIMM Z790 boards, so again it comes down to the specific board, what it offers and how much it costs. Beyond that the chipset name is just marketing.