Without specifics it’s hard to answer. But, DX12 is junk and shouldn’t be used in BFV. On top of that you only have 8gb of slow ram in single channel. BFV is brutal on CPUs and you have a locked quad core. All these things are combining to reduce framerates. If you reduce graphics and framerates dont change you’re cpu bound.
Few things to try tho:
- uninstall gpu driver with ddu in safe mode
- ensure bios and all mobo drivers are up to date
- set nvidia panel and windows to max power/performance