Docker image build is 3 times slower than the normal build

[Paul123]

I’ve received a response from them. They recommended using machine executors. As mentioned by @eliasdorneles the problem persists even with machine executors.
This is what I’ve tried:
Comparison of build time (the npm run build command):

Docker executor: 14783ms + 21555ms = 36338ms (36.33 seconds in total)
Machine executor-docker build command: 25194ms + 42171ms = 67365ms (67.365 seconds in total)
Machine executor-docker run command: 25188ms + 43326ms = 68514ms (68.514 seconds in total)

Edit:
Added config.yml

@config.yml

# Testing the performance of docker build vs normal build
version: 2

jobs:
  job1:
    machine:
      image: circleci/classic:latest
    steps:
    - run:
        name: Build from dockerfile
        #        Dockerfile:
        #
        #        # Same base image as in config.yml
        #        FROM circleci/node:8.11.1
        #        # cd to home/circleci to avoid any problems
        #        WORKDIR /home/circleci
        #        # Run the same commands
        #        RUN git clone https://github.com/cezerin/cezerin && cd cezerin && npm i && npm run build

        command: docker build https://gist.githubusercontent.com/PaulGgithub/c4359495a31961e8217fb463756444c9/raw/d01b96d7a3cb093d5bb05a47e656711373afc558/Dockerfile
        #################################################
        #    Spinning up a container and running the same commands as in step 1. Notice how slow they are executing.
        #    Build inside container
    - run:
        name: Build with docker by executing commands inside a container
        command: >
          docker run -it circleci/node:8.11.1 /bin/bash -c
          "cd home/circleci/ && git clone https://github.com/cezerin/cezerin && cd cezerin && npm i && npm run build"

workflows:
  version: 2

  tests_to_run:
    jobs:
    - job1