update simulator README

old-commit-hash: 1830a87d9a

tools/sim/README.md

@@ -30,12 +30,14 @@ You can control openpilot driving in the simulation with the following keys
 To see the options for changing the environment, such as the town, spawn point or precipitation, you can run `./start_openpilot_docker.sh --help`.
 This will print the help output inside the docker container. You need to exit the docker container before running `./start_openpilot_docker.sh` again.
 
-## Performance
+## System Requirements
 
 openpilot doesn't have any extreme hardware requirements, however CARLA is very resource-intensive and may not run smoothly on your system. For this case, we have a low quality mode you can activate by running:
 ```
 ./start_openpilot_docker.sh --low_quality
 ```
+NOTE: [CARLA requires](https://carla.readthedocs.io/en/latest/build_docker/) an NVIDIA graphics card.
+
 You can also check out the [CARLA python documentation](https://carla.readthedocs.io/en/latest/python_api/) to find more parameters to tune that might increase performance on your system
 
 ## Further Reading