face-api.js - Why is browser's faceapi.detectAllFaces() is faster than server's?

I want to use face detection on my server-side. Therefore, I found face-api.js for this task. I discovered that each call of faceapi.detectAllFaces() lasts for ~10 seconds. But when I start the browser-example, only the first function lasts 10 seconds and all the next lasts less than one second.

My server-side code (you can see a similar code in ageAndGenderRecognition.ts):

import * as faceapi from 'face-api.js';
import { canvas, faceDetectionNet, faceDetectionOptions, saveFile } from './commons';
await faceDetectionNet.loadFromDisk('../../weights')
await faceapi.nets.faceLandmark68Net.loadFromDisk('../../weights')
await faceapi.nets.ageGenderNet.loadFromDisk('../../weights')

const img = await canvas.loadImage('../images/bbt1.jpg')

console.time();
const results = await faceapi.detectAllFaces(img, faceDetectionOptions);
// ~10 seconds.
console.timeEnd();

console.time();
const results2 = await faceapi.detectAllFaces(img, faceDetectionOptions);
// ~10 seconds again.
console.timeEnd();

Why faceapi.detectAllFaces() (except first call) is faster in browser-example than in ageAndGenderRecognition.ts? And which similar thing I can to do to my faceapi.detectAllFaces()-function has the same speed?

from face-api.js - Why is browser's faceapi.detectAllFaces() is faster than server's?