
ASUS PN40-BB009MC
Intel Celeron N4000
ASUS PN40-BB009MC
Intel Celeron N4000
The description and the product name are different, and it is probably the model that has a fan (built-in fan: 1, as in the detailed description) and is not fanless. If you want to install 8GB RAM, you have to use DDR4-2133 (instead of 2400). See ASUS' Qualified Vendor List: https://dlcdnets.asus.com/pub/ASUS/Desktop/Vivo_PC/PN40/PN40_RAM_report_20180307.pdf
I don't think the Celeron N4000 needs a fan. On the QVL list I also see some 8GB RAM modules with 2400MHz.