A:Answer On this link: https://rog.asus.com/fi/laptops/rog-zephyrus/2021-rog-zephyrus-g15-series/spec (site is quite a mess and some data is just missing)
the models
GA503QM-HN125T,
GA503QR-HQ017T,
GA503QR-HQ008T,
GA503QR-HQ092T,
GA503QR-HQ115T
have 8GB RAM soldered. Max Capacity of RAM is 24GB.
Models:
GA503QS-HQ004T,
GA503QS-HQ021T,
GA503QS-HQ071T and
GA503QS-HN072T
have 16GB DDR4 on board.
On this site: https://rog.asus.com/laptops/rog-zephyrus/2021-rog-zephyrus-g15-series/spec
the models
GA503QM-HQ120R,
GA503QM-HQ121R,
GA503QR-HQ098R,
GA503QR-HQ099RS
have 16GB RAM on board. Max Capacity of RAM is 32GB.
Also QM models are 3060, QR should be 3070 and QS 3080.
There is no single word about this BB model (GA503QR-211.ZG15) anywhere. And it is one of those 8GB soldered model. That should be the reason for cheaper price.