i have a RX 560 that has only 4 GB's of VRAM, when reBAR is enabled all my dx12 games slow down when: switching scenarios or changing graphics settings

here is RE village with rebar enabled in bios:

here is with rebar disabled:

here is with rebar enabled but with no_upload_hvv:

edit1: theres also massive performance loss when changing a game from fullscreen to borderless full screen with rebar enabled