Frigate bare min yml file?

i only have 1 camera with Frigate. my HA with Frigate add-on is on an i3 laptop with 8gb ram, with the NUC hassOS image.
any idea why my sensor.cpu sometimes hit 100%?

this is my Frigate.yml file. is there anything i can do to optimize the CPU so it does not work so hard? as you can see, i only care about person detection as I already have an Amcrest NVR to record videos 24/7. i would like to add 2 more 4K camera at the full 4K resolution instead of the smaller feed of 640x480

detectors:
  cpu1:
    type: cpu
mqtt:
  host: 192.168.1.229
  port: 1883
  # Optional: topic prefix (default: shown below)
  # WARNING: must be unique if you are running multiple instances
  topic_prefix: frigate
  # Optional: client id (default: shown below)
  # WARNING: must be unique if you are running multiple instances
  client_id: frigate
  # Optional: user
  user: mqtt2
  # Optional: 
  # NOTE: Environment variables that begin with 'FRIGATE_' may be referenced in {}.
  #       eg. password: '{FRIGATE_MQTT_PASSWORD}'
  password: PASSWORD
  # Optional: interval in seconds for publishing stats (default: shown below)
  stats_interval: 60
 
cameras:
  backyard:
    ffmpeg:
      inputs:
        - path: rtsp://admin:[email protected]:554/cam/realmonitor?channel=1&subtype=1
          roles:
            - detect
            - rtmp
    width: 640
    height: 480
    fps: 10
    rtmp:
      # Required: Enable the live stream (default: True)
      enabled: true
    snapshots:
      # Optional: Enable writing jpg snapshot to /media/frigate/clips (default: shown below)
      # This value can be set via MQTT and will be updated in startup based on retained value
      enabled: true
      # Optional: print a timestamp on the snapshots (default: shown below)
      timestamp: true
      # Optional: draw bounding box on the snapshots (default: shown below)
      bounding_box: true
      # Optional: crop the snapshot (default: shown below)
      crop: False
#      # Optional: height to resize the snapshot to (default: original size)
#      height: 175
      # Optional: Camera override for retention settings (default: global values)
      retain:
        # Required: Default retention days (default: shown below)
        default: 10
        # Optional: Per object retention days
        objects:
          person: 15
    objects:
      track:
        - person

thanks for the link. none of those suggestions worked. i added:

      hwaccel_args:
        - -hwaccel
        - vaapi
        - -hwaccel_device
        - /dev/dri/renderD128
        - -hwaccel_output_format
        - yuv420p

also added mask to hide the time stamp on the video:

    motion:
      mask:
        - 573,0,640,0,640,61,511,69,0,43,0,0

hopefully the Google Coral chip will help out