Non-modded Fallout 3 (2008) isn't a resource-intensive game - the game only uses two CPU cores - so it can run on any modern gaming computer. I have a heavily modded game (check my mod list) with 2K/4K textures + ENB, and I record the gameplay with OBS, so I built a gaming PC to handle that.
My specs are (2019):
RE: Fallout 3 Walkthrough (Modded) Part 250